I've been playing WipEout since the day it came out on both the SONY PlayStation and also the SEGA SATURN. Recently I got a neGcon for my PSX and its awesome with WipEout. I also recently aquired another working SEGA SATURN and I have been playing WipEout on it all day. I must say that I really feel that the SEGA SATURN version of WipEout is superior to the SONY PlayStation version of the game.
The SEGA version has faster gameplay (much faster, not just a little bit), with floatier physics, brighter graphics, better control, louder crisper sound, and even has different songs on the sound track. I haven't compaired song lists side by side so Im not sure if songs from the SONY version are missing on the SEGA version, but I did notice that there were some songs on the SEGA version which are not on the SONY version.
Not all is better on the SATURN, the game's frame rate is slightly lower and so is the texture resolution. However the game seems to have extra artwork here and there during loading screens and menu screens, and the game also appears to have extra background elements in the form of geometric objects that are trackside here and there. Colliding with the sides of the track seems to slow you down less on the SEGA, and it's easier to fly above or below another contender. The PSX version of the game has superior transparentcy effects for smoke trails and such, and also has better sound modulation (on Altima IV on the PSX when you reach the apex of the huge climb, the sound of the game and music becomes resonated, the SAT version has no such effect).
I haven't had the pleasure of trying out WipEout 2097 on the SEGA SATURN but I definately will make that a goal of mine to obtain one.