We need to get the obvious out of the way first: Disney's "Aladdin" IS showing in IMAX 3D in some cities! We need to state this upfront because for the sake of this argument, that would normally be in play for this discussion. The problem is that IMAX is being really stingy with how many 3D screenings of the film they provide. Most theaters only have one showing and that one showing is typically early in the day, long before most people get out of work and school on the weekdays. Since the weekend and Memorial Day has passed, there is virtually no guarantee of hard working Americans being available to see this screening (and there is an even greater chance the 3D screenings will be dropped altogether for the second week). For all intents and purposes, the IMAX 3D version is effectively off the table for anyone who doesn't want to call out sick sometime this week. That means we must look critically to see if the 3D effects in "Aladdin" are worth giving up giant screen experience.
For what it's worth, I don't think "Aladdin" is a movie worth seeing in the first place. I wrote a review on it, but the long and short of it is that this is a movie that is a pale imitation of the original, doesn't add anything truly great to what was already there, and that you will have an equal (and outright better experience) if you stayed home and rewatched your BluRay of the original. Let's say you do want to subject yourself to Will Smith's blue Genie though (who - in all fairness - was the best thing about this remake), it's good to know that while the movie wasn't filmed in 3D, director Guy Ritchie was aware it was going to be projected in 3D. Therefor there are MANY shots that take advantage of the third dimension! The opening shot alone makes a strong case for seeing the film in 3D, as the camera pans over the water, the credits turn to dust, and the scene ends with the viewer going in and through the citizens of Agrabah. For some time after the movie doesn't make much use of 3D until we get to the "Friend Like Me" musical number (the other highlight of this film), in which 3D highlights the sheer insanity of the sequence much better than 2D does.
Ironically, this is where the 3D starts to cool a bit. The "Prince Ali" number is rather flat in how musical numbers should be, so there's not much of a draw there (although the ostriches and confetti coming at the audience was sort of cool). You would think "A Whole New World" would benefit from 3D (since the characters are flying on a magic carpet and all that), but the scene is oddly still and quiet, so the effects aren't put to much use. I'm sorry to say this version of the movie does NOT have a sequence where Aladdin fights a giant snake, but Jafar still turns into a red genie, so that's kind of neat! Otherwise, the movie is fairly pedestrian. Ritchie does include some slow motion shots that highlight the 3D aspects, however those sequences are fairly brief and few and far between. So what do I ultimately think? Well, if IMAX 3D IS an option (and you insist on seeing this movie) I would go with that! If it's not, the ideal middle ground might be Cinemark XD 3D or AMC Prime 3D. They aren't as big as IMAX screens, but they are of pretty decent size, so it would be a suitable compromise.
If you have to choose between the two, I would lean towards the 3D version, but only slightly (and not enough to recommend you go out of your way to a theater that isn't close by). In the case of "Aladdin" there is a lot of reason to recommend the 3D version, but not enough to completely shun the IMAX release. This is one of those experiences that toe the line on whether or not the 3D is integral to the movie. On that level it probably isn't, however the few scenes where it is used cleverly is enough to give it the edge that the 3D version is likely the one you'll want to see.
