Ok, I'll leave this thread to be about the IMAX presentation as I've put my opinion of the movie itself in the other Potter thread.
I hate to say it, but I was a bit disappointed in this IMAX presentation. I guess I was expecting a bit much as I was basing my expectations on the other 2 films I've seen presented in IMAX. The Matrix Reloaded & Batman Begins were the only other 2 films I've seen shown in IMAX (that weren't shot in IMAX). And those 2 films are supposed to be the 2 best live action films as apparently Polar Express is the best IMAX DMR release.
Batman was a good bit better than Reloaded IMO. And Reloaded was a good bit better than Potter 4. I was sucked into Batman & Reloaded on many different occasions watching those in IMAX. But there wasn't really any scene that did the same thing to me in Potter.
The sound seemed dull & lifeless. Which wasn't the case at all for either Batman or Reloaded.
The picture was rather soft as well. But I'd guess with all of the SFX in the film they had to soften the look of the film so that the effects blended in well with the live action.
I saw both Batman & Reloaded 3 times each in IMAX. I don't think I'll bother doing the same for Potter.
Yes, if you can see it in IMAX by all means do so. But I doubt you'll really need to see it in IMAX more than once...