If you don't own one, you can't know a whole lot about the gameplay. That is, unless you put in more than a handful of hours on someone else's Xbox with a Controller S instead of the supersized plastic block controller.
When I first got it, I was a little put off by the assumption that you'd want to use an analog stick for the main control. Analog sticks have *way* too much play and nowhere near enough resistance for me in general, so I prefer the twitchier D-pads and do great with them. Analog sticks just fly all over the place with no resistance until you hit the extreme (stopping with nowhere else to go), causing me to move in jumpy motion as I correct for over- or under-moving. I've experienced this with both SGT2002 and JSRF, the two games that it came with. After a few hours with it, though, I've gotten better with the analog stick and I'm able to be at least competent now.
Gameplay to me is how well the game does what it is trying to, how intuitive actions are within the game and menus, and how the game shows motion (camera angles, visibility, etc). Strictly dealing with SGT2002, I can happily say I like the gameplay as much or better than GT3. Load times are faster, AI is better, physics are just as good, damage is accounted for, routine maintenance is accounted for, graphics are on par, music is worse, sound effects are better, menus are MUCH better, and - perhaps most importantly - I can have multiple saves without having to purchase an additional memory card... well, ANY memory card at all! It really is a great game.
And, when it comes to games, Xbox can match or exceed any Sony offering in any genre. Racing? Sega GT 2002, Rallisport. RPG? Shenmue II, Panzer Dragoon Orta. Shooters? HALO, Gunvalkyrie, MechAssault, and many others. The list goes on. Anything that both consoles have, the Xbox version looks, loads, and is better. Anything exclusive to Sony can be matched or exceeded by an Xbox version.
Now, if you just hate the fact that a big company like Microsoft is in the market (and this makes me laugh because apparently you've neglected to observe just how huge and wealthy Sony is as a company, not to mention every bit as predatory and profit hungry as MS), then go ahead and say that, because it makes a LOT more sense. I have nothing against Microsoft, preferring to judge products by how well they meet my needs, and the Xbox is the best game system on the market, meeting or exceeding my demands of a console (so far... heh).
This doesn't make GT3 a bad game or PS2 a bad system - I plan to play some GT3 tonight in fact - I'm just saying that given the two, it's obvious that the Xbox is the better platform and any unbiased comparison will say the same.