I'll probably buy Quake 4 on my 360 as I still use it and I'd imagine the graphics of that and on PC aren't drastic enough to make me wanna tinker with PC gaming lol. Good description - also enjoyed Doom 3!
Since this is an old game, there isn't too much of a difference between these 2 versions. But the performance is still better on the PC, along with some image quality.
The Xbox 360 version has significantly muddier textures, especially the game's wall and ground textures.
In addition, the frame rate is sort of a mess. At some points, it gets so bad that the whole game starts to slow down.
I mean you'll know when that's happening because the weapon's rate of fire slows down, lol. Even when there's no activity onscreen, just viewing the environments is enough to make the game run at a sluggish/choppy rate. While there are still some cool-looking areas, the FPS still takes a hit, dragging down the entire experience to some extent, if we compare this to the PC version.
But otherwise, you should be OK.