So, after arriving an hour before the movie started (as I do when there is no allocated seating... why does IMax not do allocated seating! GRRRR) we finally get let into the cinema with polarized glasses in hand. I was stupidly excited by the idea of seeing this in s3D, I guess because the previous movie had quite an impressive visual style in 2D and thought it would translate well in s3D.
So, we get a single preview which was for 'Christmas Carrol' in amazing s3D. WOW!!! that looks so good, I think I may go and see it. Then the feature movie starts and you see some great s3D text coming flying at you. The text is done really well and it feels like you are flying through the letters BUT... the non animated stuff starts to be shown and it looks flat. Trying to stay positive, I figure they are trying to start off fairly flat so the audience can let their eyes adjust to the effect. But as you see more and more, I start to notice strange artifacts.
Things like harry's eyes. Behind the glasses, it looks like his eyes are flat images that have been stuck to his glasses! eeep! quite off putting. Also, it appears that whenever there was semi-transparent surface through which you were seeing things, the effect was either wrong (as if the surface was stuck to the character/object you were seeing) or NOT THERE. 
One obvious scene saw harry looking through a foggy window... it was FLAT! I know that it would be almost impossible to do this correctly in s3D conversion from 2D but was disappointing all the same. 
On the plus side, there was a sequence that I assume was computer animated flying through streets and this was great!
It only lasted for about a minute out of about 30 mins of "Stereo" 3D.Overall, I enjoyed the movie. It is quite well done and the story makes sense following on from the previous chapters. The character development is a little obvious and predictable, but that's what I've come to expect from the Harry Potter series. It has an obviously well done visual style similar to the previous adventures in the series.
As for the s3D, i feel let down. The conversion from 2D to 3D has obvious flaws and I felt that it didn't really add anything in this case. I may be overly critical of this, given that I was looking for how well it was done from a technical side, but others who aren't so into the s3D that I went to see it with also said the same thing... they weren't commenting on the technical flaws, but that it just added nothing. I feel that, had it been actually shot in s3D, it could have looked very impressive, but since it was a conversion from 2D, it looked somewhat off so lost any advantage s3D could have.
Unfortunately, I think this will be a setback for s3D since those people who have not yet seen a well done s3D movie will be put off from watching one due to seeing one that is not done so well.
Maybe the preview of Christmas Carol (which was done well 8) ) may make up for it a little though. I just hope that people give up trying to do 2D to 3D conversion... IT DOESN'T WORK! And... I wish they'd pass a law to outlaw this process.
)