Lightyears beyond. Tron was okay, but the special effects in Avatar were good enough to look real to the layman. Hell, I knew it was fake, but I wanted to believe it was real so bad!
The effects of the movie Avatar stands out as a more jungle-like theme and I love to admit the details of the backround are amazing, same with the details in Tron except the fact that it's into a more Sci-fi backround.
