I'm bored, I might as well add my two cents
Magic Kingdom
MOST UNDERRATED: Stitch's Great Escape--forget what used to be there, it's still a very unique and one-of-a-kind theme park experience. I don't see anything like it anywhere else and I think more people would appreciate it had it not been for Alien Encounter. I would say the TTA, but everyone here seems to love it already.
MOST OVERRATED: Peter Pan--seriously have never seen the appeal of this one. It's loud, squeaky, cheap, weird, hard to hear, hard to follow, small, cheesy, and always draws in huge lines.
Epcot
MOST UNDERRATED: The American Adventure--it's tucked away in the very back and rarely is full but when I get to see it, I always get goosebumps. Not only is it a great showcase of American history, it's a great showcase of storytelling technology, from revolutionary scene changes and innovative animatronics. And it's in a beautiful venue too.
MOST OVERRATED: Definitely Soarin'. It's good, but not worth such a long line in such a boring building. The whole thing, from the showbuilding being visible from World Showcase to the awkward queue and exit to it's California video, this one's just too lazy of an effort to get worked up about.
Hollywood Studios
MOST UNDERRATED: The Great Movie Ride--Disney's best dark ride. Amazing, huge, immersive sets, a healthy length, a unique role for the live tour guides, and an overall great ride! This one always leaves me smiling it is just magnificent.
MOST OVERRATED: Fantasmic--I never understand what exactly those thousands of people are lining up for. As if the show wasn't weird enough, it's far inferior to its Disneyland cousin. Maybe I'd like it more if the crowds weren't so outrageous.
Animal Kingdom
MOST UNDERRATED: Dinosaur--in my opinion the most underrated attraction on Disney property. I love the EMV technology and while I admit it's inferior to Indy, it's still got lots of cool effects and realistic sets. And the intensity is unprecedented for a Disney ride these days. I love this one, my favorite at the World!
MOST OVERRATED: Festival of the Lion King--never saw the huge appeal, like I get that the songs are moving, but I don't like the flimsy look of the sets and props, and I've seen the Broadway show which obviously has better production value. Don't get the hype, unless it's just people desperate for something to do at AK and will take what they can get lol.
Universal Studios
MOST UNDERRATED: T2-3-D-- Hands down the best 3-D show of all time. I mean, it's directed by James Cameron himself! And it holds a record for most expensive film-per-minute ever. I love the execution (generally believable, and little suspension of disbelief is needed as is with most theme park attractions), the effects are still breathtaking, and the whole thing has just been kept up so well. I can't believe people are calling for this one to get taken out.
MOST OVERRATED: Shrek 4-D--terrible show. Theming is non-existent in the theatre, the film execution makes no sense, the seats are ridiculously noisy and move at times where they shouldn't...like someone else said, I can't believe Shrek is used to promote USF with a terrible show like this.
Islands of Adventure
MOST UNDERRATED: Dragon Challenge--I rarely see a line for this one, and its proximity to such a major player like FJ, plus its reputation as being a vomit-inducer, hurts this one I think, but it really is the best coaster on property...it combines high-speed loops, relentless energy, unique maneuvers, and comparatively strong theming for a coaster all in inverted form...love it.
MOST OVERRATED: The High in the Sky Seuss Trolley Train Ride--always more than half an hour to ride this when I walk past. Really? I know queue time isn't a measure of popularity but the fact that people are willing to wait that long is beyond me. It's short, strange, and really really boring.
SeaWorld
MOST UNDERRATED: The Wild Arctic--love how the simulator transports you to the exhibit, it makes the actual pavilion seem all the more authentic, and the theming inside is great. The simulator is actually good too, for not being one of the major theme parks. In my opinion, it's better than the original Star Tours.
MOST OVERRATED: Kraken--I love the ride, but I don't get what makes it so unique. The floorless feature is useless unless you happen to be sitting in the front, and it really doesn't get that much speed; all the maneuvers are handled pretty gently. I don't get the love for it.
Busch Gardens
MOST UNDERRATED: Montu--fantastic layout, breakneck pacing, and tons of inversions...the only thing that puts it above Kumba in my book is its inverted feature and the fact that they actually attempted theming, which comes off as pretty good.
MOST OVERRATED: Cheetah Hunt--overhyped new ride that in reality is slow, long, and dull. And seriously, if the vehicles are cheetahs, why do we climb to the top of that tower (which slows the pace down so badly) and then do a zero-G roll?! I would never wait more than 5 minutes for this one but honestly, I don't even know if it's worth the 3 minutes it takes to ride.