I agree somewhat with Tumbler. I'm sure the game will rock but it has been outdone engine wise already in most ways. It uses Havok, which while modified quite a lot, has been used extensively in many games already, and that was supposed to be the one major feature in the engine.
Doom3's 'physics' aren't as good as the havok engine in so far as boxes tumbling and debri flying or what ever, because it uses it's own proprietary physics engine. However it's physics engine isn't JUST falling boxes and such, it's very innovated 'ragdoll' physics which is better then any before it, and it's sound engine, which is also quite amazing and very innovative.
The HL2 vids still look quite awesome and I'm sure the game will rock, maybe even be better then Doom3. But in terms of the technology of Source, it is good, but it's been outdone IMHO.
Course if people remember back when Doom3 was first shown, a lot of people insisted it was pre-rendered graphics. Id have to prove to them that it was real time, hehe.
As to the fact that steams survey shows more poeple are using low end nvidia cards then high end ati cards. Thats because most people cannot afford a top end graphics card. That and really the FX5 series of nvidia cards were initially quite disappointing. I agree with this and I'm an nvidia fan

But that still doesn't dispute the fact that valve delayed the game originally because they realized how many people who were using steam were using nvidia cards. Especially the lower end ones.. which were severely lacking in frames at the time. If like 400 out of the 550k people using steam are going to get terrible framerates in your game, you have a problem.
Also it might be interesting to note that the nvidia deficiencies in the source engine are no longer such a bad case. Evidence of this can be found in troika's new source based game Vampire: Bloodlines, which is displayed on nvidia FX5 series cards and running very smoothly. How each card will fair in terms of performance though.. we'll have to wait and see. I'm sure it will be ATI though as they are lining valves pockets.
This comment was edited on Aug 20, 00:01.