txtworld,
Currently a mouse hack, but I was planning on switching that out. I just haven't played in a while. If you do a search, I'm actually use the P360 joys that I made into optical rotaries.
Xiaou2,
I use buttons for the up/down levels. You use 4 buttons, but you don't really operate them all at the same time. IIRC, you can only have 3 discs on the screen so you aren't constantly pressing fire. Because of that, you also have to set your shots up and you plan ahead. Once I see a shot, I tend to fire all 3 discs at once at SARK(?) so that I get the angle right and he can't move left or right. It gets faster during the later levels and there is more strategy, but I tend to do the same thing unless I see a quick shot.
It just comes down to different strokes for different folks. I don't have an actual tron sitting in front of me to compare side by side, but last time I played it I just didn't like playing it that way and preferred to aim like I did in Ikari. It's probably the same reason why I can not use a keyboard and mouse to play a FPS, but a lot of other people say it's the only way to play a FPS.