Yes, like everyone states, the special effects are amazing in IMAX 3D. The fantasy world created by James Cameron's CGI crew is spectacular.
However, 3 hours! After the second hour, I was antsy to get out of my seat. This is not Gandhi! And even Gandhi had an intermission.
I felt this movie was more geared towards a cartoon for kids. The plot was too predictable and some parts I felt like it was a complete rip from Lion King's music. I walked out at 2.5 hours...during the war scene...too loud...been there done that in so many movies. Dad stayed behind. He regretted it.
Go for the special effects, but don't expect a novel storyline.