The game does look like a steaming pile of eft-refuse on PC without some serious code tweaking, but Windower and the out of game options can get it to look pretty close to PS2 and I'm assuming 360.
At max settings on PC, the game looks FAR better than it does on PS2. Believe me, I played both for several years and can say that without the shadow of a doubt. Tweaking the code using windower and config options certainly made it look better on PC, but even without it was leaps and bounds better than what was possible on PS2.
On topic, I think pretty much any of the servers at this point should be pretty active. There aren't all that many, and there are still a good amount of people who play XI, so I don't think you can really go wrong.