Tron is probably my favorite movie of all time! A fun adventure movie that's amazing to look at through the entire movie thanks to the immense effort put forth by the entire team, even if the story goofs up in a few places. If you have the time, watch The Making of Tron documentary where they go over (and show) some of the processes they used and show them as well!
One thing I can't get over in regards to the sequel (Legacy) is how it changed the aesthetic of the computer world from nice bright neon on white and vivid purples to all black and neon blue or orange! Legacy is jam packed with CGI but it's still less visually interesting to look at (in my opinion) because of the lack of color. Not to mention it moves away from the "power to the users/believers" angle of the first film to try and take a philosophical stand on everything that amounts to meaning nothing.
Tron is a truly unique movie in everything it did, and my greatest sadness is that nothing that came after it has the same look and feel as the original. The closest we get is the world they had in Kingdom Hearts 2...