These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Adaptation Displacement: Few people ignore that the whole series is a franchise, that is older than it looks (15 years as of 2012), that it was originated from a videogame (that wasn't exported until the Video Game Remake of Medarot 2 for GBA... in 2002/03). Or that the manga that came out is basically an adaptation of the videogames. The anime series took elements from both the videogames and few others of the manga (mostly, the Medarot 2 adaptation)... and yet, the first thing that come to mind to people is the anime series, that was done 2 years later the original release of Medarot for GB... (especially without a simple research on the net in these days...)
If the games are to be believed, Banisher can only deal damage by counterattacking, and since Metabee headshot it (and Metabee is deceptively strong), he presumably dealt enough damage to knock him out. (Either that or the robot is just too weak to fight, and Baron instead tries to scare opponents into submission.)
Baron is also an anticlimax boss in game as all he can do is counter attack, meaning he can only hurt you if you attack. You might get hit once, but if you have any sense you'll them spam Medaforce which bypasses counter while he stands there doing nothing but trying to counter.
It's a bit more complicated than that. Since the series is based on certain events from the videogames (M1-M2 by the time of writing and airing the anime), they do reveal pretty much that the medals are older than humanity and are from alien origin, but when they were discovered, Hushi and Akihabara started to use them as mind and soul for the robots they were bulding (or at least what it appeared to be in the manga adaptations). Of course, there is not denial that this could have been worked much better than what was shown in the first place.
There's also the fact about Brandon. A character who only appeared in two episodes with minimal screen time, suddenly shows up in the season finale. Only to reveal that he was actually an alien.
Awesome Music: The dub had a surprisingly epic opening theme. An instrumental version would play during fight sequences.
Crack is Cheaper: Medabots are pretty expensive to get and maintain. Getting a tin PET is one thing... getting a medal is another AND getting the armor (or even REPLACEMENTS of some armor parts) is a complete different story. Apparently, according to the manga adaptation of the videogames, getting a female tin PET is more rare to find, and purposely more expensive to get.
Another case of Fridge Brilliance, since Metabee's armor WAS old and discontinued, Ikki not only used some of the medaparts that he got in the course of the original series, when he pretty lost parts (or the whole) of his armor, even he repaired him at times.
Creepy Awesome: Beast Master (Robo Emperor) and God Emperor (Mega Empreror) are two of the most popular medabots for the Japanese fandom (as of a recent 2012 Japanese poll results held at Nico Nico Douga. The first is Nightmare Fuel material, but the second is one of the most recurrent medabots used in the whole franchise of the games.
Ugly Cute: The thing with God Emperor could be a case of this. Compared to Beast Master, it's... a bit more normal to like because of its design (besides being a powerful medarot/weapon). To the point that Kirara, in Medarot 2, has one of these...
Die for Our Ship: Poor Oceana. The dub did not help by moving her first appearance, originally the eighth episode, all the way to the filler section... at least thirty episodes later. After the ShipTease episodes about Metabee/Brass. Cue the fanbase treating her like a rabid whore who wants to steal Metabee from Brass, who is suffering for her love. Karin doesn't necessarily get this as she's dumped on Kouji to make way for Ikki/Arika or Ikki/Kikuhime.
Ear Worm: Both the American Opening AND the original Japanese opening could be this for anyone that have heard them.
Family-Unfriendly Aesop: Episode 20 has Ikki in a race against time to either get enough points to represent Japan in the world tournement, or save his mother from the Rubberrobo Gang. He manages to save her, but Metabee's too busted up to fight another battle for the Last Lousy Point.. guess we'll get a lesson about how you should do the right thing even if you're not rewarded, and about not pushing your friend beyond his limit... nope, Ikki is a coward for not wanting to fight, all his friends heckle him and he accepts. Say whaaa.?
The first Medabots had as one of its strong points, its pacing — it managed to insert a lot of plot and character subplots in few episodes, and yet never felt (too) rushed. Spirits, on the other hand, stuck with a single plotline (Kam's) through its entire run, and suffered dearly for it, as episodes had to constantly reinforce the status quo to stop the plotline from ending, thus advancing the plot ever so slowly for its 39 episodes. The exclusion of most of the original cast helped to make that more apparent — with less characters, episodes had to focus exclusively on Ikki, Arika and, sometimes, new character Zuru, making stories less varied. Spirits did away with the first series' strengths, and played up its weaknesses.
Fridge Brilliance: In the dub, Hikaru had renamed himself as Henryafter the Ten Days of Darkness incident, but in the original version this doesn't happen. However, if you think about this, the kids react very vague and in 'ah, how a coincidence' because of the mention of Hikaru Agata. That is because at the first time Hikaru interacts with Ikki, he is called 'Combi-nii-chan', and later when he starts assuming his 'Big Brother Mentor' role, the kids start calling him solely as 'Hikaru-nii-chan'. The kids, at the point when Joe Swihan revealed that Uchuu Medarotter X was Hikaru Agata, never knew about Hikaru's last name. Until, of course, Ikki started putting the pieces of the puzzle together to find out that their friendly convenience store clerk have always been Hikaru Agata.
Better yet, since there wasn't any record from the event, they couldn't research a photo of Hikaru Agata. Besides, there could be other people going with that name in Japan, too.
Much more as in Fridge Logic, is that this is hinted since the FIRST episode. That is, though, if you are not familiar with the videogames (since the anime is much more of an amalgam retelling of the first two serials, just exactly what the American and International audience were in the first place). Of course, Nelvana had to ruin it in the dub of the series because Hikaru, in the original, named Metabee in the first place, not Ikki... and tried to repair this later. Heartbreaking in a sense too, since the viewer doesn't really perceive how dramatical is this until much later in the series.
Fridge Horror: In episode 25, whenever Dr. Meta-Evil's henchman fails him, he turns them into teddy bears. Can you imagine what it's like to stay as an inanimate object, for who knows how long?
Hilarious in Hindsight: Ikki and Erika mocks Henry for trying to sell them an old KBT model. And then, guess which model does Ikki buy in later?
Ho Yay: Fans almost often tend to ship Hikaru and Ikki... Mhmm... guys, do you remember that Ikki is an 8 year old kid and that Hikaru is in his late-teens? Squick indeed. However, it's a bit of a popular ship...
Memetic Badass: Coach Mountain is an interesting example as other characters in the show view him as this, though the fandom agrees.
Arika: "I heard he used to be a strong man at the circus and could bench press elephants. I also heard he chiseled out the faces on Mount Rushmore with his bare hands!" Ikki: "And he stopped an erupting volcano by plugging it with his butt!"
Even Damashii has an episode that invokes this: just imagine that there could be a medabots junkyard full of zombies with a cute female medabot as their leader, who is way too damaged and her eyes look like are 'tearing' blood (or oil). Yeaaaahhh...
Robo Ship: Metabee/Oceana, Metabee/Brass... Metabee/Rokusho... and even Medabot OCs with other Medabot OCs.
Also, some Medabots with their own owners... Yeeeeesh. (Though some fanarts depict the medabots as humans... it doesn't help some owners are 8-10 year old kids).
Superlative Dubbing: Arguably one of the best dubs - for its time, and the target audience, of course.
They Just Didn't Care: Nelvana arguably pulled this in the English Dub. The airing of some of the first 20 episodes were pulled until MUCH later because they could just wanted to accelerate the action of the anime OR because they accelerated the appareance of Rokusho (this is pure speculation), making a Dub-Induced Plot Hole later.
Could be also applied when the animation of Damashii changed from Bee Train to Trans Arts, since the obvious dissapearance of many characters of the first series. Sure, it could be applied to they 'just moved on with their lives'... but considering that maybe not all the animation staff didn't make it through the change of animation studios... this could have been also reflected with the series. To the extense that certain story elements didn't either make it... and could only be related to cameos in the ED, because the character designer HAPPENS to have directed it. But almost no one of the ED of ANY series is canon with their anime...
Unfortunate Name: For English speakers, "Ikki", due to the fact that it is pronounced as "icky" in the dub, a slang meaning "Gross". Many a kid chuckled whenever the trailers mentioned lines like "And the winner is... Ikki!"
Granted, it's actually pronounced "Ee-Key", but the spelling made many a person think it was pronounced as "Icky".
Values Dissonance: In Phantom Renegade: Unmasked (season 1, episode 11), Seamus McRaker slanders Ikki because he believes Ikki is the Phantom Renegade. At the end of the episode, Ikki defeats Seamus in a Robattle and Arika publishes an article that clears Ikki's name but Seamus faces no legal comeuppance for slandering a child. What makes things even more stupid is that everyone believes Seamus' stories without giving Ikki the opportunity to explain himself. In fact, everyone ignores that Ikki is a kid while the Phantom Renegade has been proven to be an adult. Adults Are Useless, indeed. The whole episode operates on Rule of Funny.
If she hadn't had such a feminine voice, it would have been hard to tell that Spirits' Black Beetle is a female-frame Medabot.
Hell, the Latin American dub even turned her into a guy. It's that confusing.
Ikki for his very girly voice, name that rhymes with "Nikki" and a topknot hairstyle. It doesn't help that there is at least one scene that involves him crossdressing.
What Do You Mean, It's for Kids?: The premise of the anime series at first could have got the attraction of the kids who watched the series back in the days. However, it took several layers of constructing the story, with its dark elements (the Ten Days of Darkness, mostly) that you could really question yourself about its kids demography... something that became superlative from other similar Mon series out there in earlier 2000s.