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.
Anti-Climax Boss: Yogoshimacritein. Despite all of his ramblings about his incompetent son, and his sucess at eliminating 4 of the Go-Onger, the Final Battle against him, both before and after the Industrial Revolution are extremely short, with his normal size failing to stop the three remaining member at destroying the power cog, and losing to the reunited team member, while his giant mode get curbstomped by Engine-Oh G-12 Finishing Move.
Awesome Music: A lot of tracks. Go-onger has a really nice soundtrack in general, but to specify:
Character Development: Quite a bit of it on the part of the Go-on Wings, who, as far as some western fans are conerned, had one of the most unliked introductory episodes but became some of the best characters in the end.
Evil Is Sexy: Kegalesia. Period. The fact that her actress is a former AV * "Adult Video" star doesn't help matters. It's no wonder that she labels herself as "in charge of Gaiark's sexiness" whenever G3 Princess is around.
"Piper" for Kegalesia. Because of her pipe costume, and her actress' former AV career.
"Chicken Hopper" for Hiroto, whose actor played "Kamen Rider Kick Hopper" in Kamen Rider Kabuto; and because he pilots Toripter, a chicken mecha.
Fridge Brilliance: Why are the revived Banki from The Movie weaker than they originally were? Because they thrive on pollution, and they were recycled.
God-Mode Sue: Engine Oh G12 during the series run was so powerful, it can beat the Bankijyu easilly. Notably, near the end of the series it was barely used until it is used for the final time against the Big Bad, where it curbstomps said big bad with 2 attacks.
Deus Exit Machina: Pretty much the reason why near the end of the grand finale more than half of the team are killed off so that the heroes can't form Engine Oh G12.
Saki's interactions with Miu are taken as Les Yay by some.
Memetic Mutation: In Japan, pictures/videos of Gunpei (or characters imitating his "Dash Dynamic!" pose) are almost unfailingly responded to with "Kakkosugiru ze..."* "Too cool..." in reference to Gunpei's final words to Gunpherd in GP Final.
Tough Act to Follow: Sentai fans weren't entirely on-board with this season, primarily because it came after Gekiranger (Which is loved by Western fans). Speaking of Western fans, many who watched it after RPM weren't fully on-board with the direction taken.