Anticlimax Boss: Dai Shi (the real one) doesn't get that much time to fight the Rangers, as the first half of his master plan is to resurrect all his fallen generals. He does get to engage the Rangers and 2 of the Megazords, but he goes down after Jarrod weakens him and then 3 of the Rangers special attack him. Fans are bitter about this, but concede that up until then, there was a load of fighting in the episode already.
Author's Saving Throw: After Overdrive clocked in over two hundred and fifty Kalishplosions (yes, really), Jungle Fury made them far more scarce outside of plot-relevant episodes.
Broken Base: The Solar Morphers split the fans right down the middle- some thought that the sunglasses made sense as all of the Rangers do complicated martial arts sequences in their morph sequence, and sunglasses are as good a disguise, as, say CellPhone morphers. On the other hand, many dismissed the entire concept of the Solar Morphers after RJ used a more conventional morpher, and also because they didn't think sunglasses could be used as morphers.
It doesn't help that the transformation devices used in Gekiranger, the Beast Henshin Claws, are integrated into the suits and referred to as "Battle Claws" in Jungle Fury.
When RJ pulls a Big Damn Heroes moment to save his dad. 'He's strong RJ,' 'So am I'
Crowning Music of Awesome: When you suffer through the Operation Overdrive opening, the theme song for Jungle Fury feels like a breath of fresh air. It helps that this is the first Power Rangers theme in a very long time to actually have harmony.
There's also the jungle-themed background music, which is heavy on the African drums. Some East Asian music is also mixed in, to match the show's kung-fu motif.
Ear Worm: The theme song is damn catchy, those vocal harmonies (seriously, when was the last time Power Rangers even did that?) just get stuck in your brain and refuse to leave.
Ensemble Darkhorse: Despite being a lesser-loved series, Jungle Fury has one of the most loved non-Ranger characters of the Disney era: Fran, the glasses-wearing, adorkable girl who slowly comes out of her shell, is well loved amongst the fans.
RJ got a good deal of praise for his unique approach toward mentoring and more laid-back persona. The fact that he was a rather pretty man didn't hurt.
Casey as well due to being a Deconstruction of Rookie Red Ranger, to the point where he's the only Disney Actor who was brought back for Super Megaforce. His actor being One of Us helps, too. It should be noted that Jason Smith, Casey's actor, was also a writer for Super Megaforce, so that could've been an additional reason.
Hilarious in Hindsight: The second wave of basic figures has their electronics taken out and placed inside "sound chips", which resemble USB flash drives. Guess what Kamen Rider Double and its toyline would be based around.
As pointed out by Broken Base, some fans didn't think sunglasses worked as morphers. Toei did, and for extra Irony, it happened in a season that some view as a direct Homage to Power Rangers. For even more irony, Saban would later skip GoBusters in favor of Zyuden Sentai Kyoryuger.
One of the toys for a Red Ranger helmet was called the "Mega Mission" helmet. Sound familiar? (Even more hilarious, Casey is appearing in the second half of Megaforce).
Iron Woobie: Non-dramatic version: Fran goes through a lot of work-related crap even before learning who her workmates really are. While a straight comic relief would either laugh it or be ignored by karma, she does get the chance to vent her frustrations.
Jerkass Woobie: Camille has Undying Loyalty to Dai Shi, and is greatly attracted to his host's body. However, he doesn't return her affections and continuously treats her as nothing more than a pawn. While Jarrod grows to care for her, Dai Shi sees her as nothing more than a servant, breaking her heart despite how much she's willing to do for him.
They Changed It, Now It Sucks: Several changes to some of the franchise's details irked fans, like the Rangers' suits lacking belts and having short gloves and shoes rather than the long gloves and boots that had been the standard costume choice for years, as well as the stronger focus on Chinese Kung-Fu as opposed to Japanese martial arts. And then there's the Solar Morphers issue...
This actually has more to do with the source footage than anything. Except for the Solar Morphers.
They Wasted a Perfectly Good Plot: In one episode, Lily is under some sort of trance thanks to the MOTW, and is acting like a selfish brute. When a monster comes out to attack the city, she stays behind the pizza place, while the others leave. Fran, fed up with her attitude, takes Lily's morpher, with the full intent of leaving and using it. Unfortunately, Lily snaps out of it, and takes it back, meaning we never see Fran morph into a Ranger.
Although it probably wouldn't have worked, given that it has been shown that simply having a Solar Morpher isn't enough to become a Ranger. We were probably spared from seeing Fran smacked around for trying to be a hero.
Vindicated by History: This season received a somewhat lukewarm response on initial airing. Nowadays, this season is more fondly remembered for its likable team of Rangers and competent Wuxia-flavored storytelling. Linkara's review probably helped it a bit.