For the record, there are two kinds of IMAX screens. There was a bit of controversy over this earlier in the year and the basic issue was that IMAX screens come in smaller sizes than the gigantic ones we normally associate with the term -- 70+ feet versus only about 30 feet high -- yet the small sizes aren't marketed with any differentiation. There aren't a lot of real IMAX screens so buyer beware. I had really wanted to see Avatar 3D on a huge IMAX screen but alas, that was not to be.
Still, we did catch it on a mini-IMAX and in 3D and the movie was just incredibly awesome. There's no review necessary because it's a must see for nearly everyone. Even if you hate adventure movies, even if you hate sci-fi and big budget schlock, this is a must see (especially in theaters) because the experience is so unique. James Cameron uses CGI and 3Dtechnology so well and the visuals in this film are just wonderful.
This won't rank anywhere near my favorite movies of all time, nor can I say it's incredible from a plot or story standpoint, but added up, this is the type of movie you go to because it'll be the talk of the town and it's worth it. People will nitpick, people will complain, but if you like having your breath taken away and being transported to a gorgeous world, it's worth the fifteen bucks. Watch it in 3D, watch it in IMAX, and heck, watch it again. I probably will.
Of course, all that is being said about how Avatar patronizes women, fetishizes native cultures, and is just like Dances with Wolves or The Last Samurai (or Pocahontas or etc.) is all true. It's hard not to overlook that aspect of the film but behind my 3D glasses, I'll suspend that part of my brain for a few hours because the movie is super awesome to look at. Do I wish the interaction between the humans and the aliens could have been more nuanced, less cliche, and imbued with greater depth (maybe a movie version of Speaker for the Dead)? Sure, but I understand that Cameron was here to create a visual spectacle and give us wow's. So yeah, I was wow-ed.