According to GameSpot’s Doom 3 Xbox review:

Extremely impressive from a technical standpoint yet behind the times from a first-person-shooter design standpoint: This is the dichotomy that is Doom 3, the long-awaited sequel from well-known Texas-based developer id Software.

Why does a technically impressive but outdated shooter deserve 8.6 exactly? This isn’t aimed just at GameSpot since the high scores have been fairly unanimous, but they’re known for being pretty strict and time has shown just how average Doom 3 was. Sites are always telling us that five on their scale means a game is average but unless they’ve made some radical changes Doom 3 on the Xbox will be just that. In fact it will be an average PC game with inferior graphics and controls. OK, if I reviewed it I’d rate it slightly above average (three stars on my scale), but I still don’t know how it can get 8.6 and higher on the same console that gave us Halo.

From what I understand, the Xbox version is essentially the same, but with Xbox Live, co-op, and some tweaks to criticisms of the PC game such as the excessive use of the colour black. This might give it a couple of points above the other version, but when you take what is essentially a massive tech demo and force it to run at a lower resolution and taking an FPS and forcing it to run with a controller (first-person shooters designed for a controller work fine, but others aren’t) you’re taking two of the games’ fundamentals away from it. Some relativelly minor additions are really outweighed by things like that.

I suppose I’m going to have to try it out to see if there are any improvements that I haven’t heard of, but as it stands all this is doing is giving ammunition to the pretentious pricks who insist that it’s because console games have lower standards and that an average PC game is considered good on a console.