The timed delay will sell more copies on the 360 vs. the PS3 to the crowd that owns both consoles. I suspect most will buy the 360 version rather than wait. That will reinforce to valve that they made the right decisions on this title and going forward will probably do the same. Assuming it does sell quite a bit better on the 360, other developers will take note and reconsider exclusive releases on the PS3.
There is one counter, however, and that is the new price tag. The new price tag means new buyers looking for new titles which may very well help sell a lot of orange box... We'll see when the dust settles...
I hate trolls.
Systems I currently own: 360, PS3, Wii, DS Lite (2)
Systems I've owned: PS2, PS1, Dreamcast, Saturn, 3DO, Genesis, Gamecube, N64, SNES, NES, GBA, GB, C64, Amiga, Atari 2600 and 5200, Sega Game Gear, Vectrex, Intellivision, Pong. Yes, Pong.
