A repost of my response to Ryan's blog:
PC vs 360
I own a decent PC and a 360. If a game comes out for both, I generally buy the 360 version (for $10 more) because (1) a console usually more reliable than a computer, with no software interruptions, viruses, etc., and (2) I don’t have to worry about upgrading my graphics hardware. I’ll buy the PC version if (1) the game is better suited to complex controls and/or mouse targeting, or (2) it’s a game I can play online with friends or family who only own a PC.
If Two Worlds has decent multiplayer, I’ll probably sacrifice better graphics for the chance to adventure with my brother online.
As for cross-platform gameplay, I think it makes sense mainly (perhaps only) for asynchronous multiplayer. Spore, for example, would be a good cross-platform game, because the players are only indirectly interacting.
But for most games, particularly action games, the problem seems to be less about fairness than about muddy gameplay. Each control scheme has powerful strengths. To make most games cross-platform, it seems necessary to settle on a middle ground than doesn’t take full advantage of either control-hardware's strengths. Such games aren't doomed by being cross-platform… they’re just made into a lesser experience.
That said, I think Microsoft is probably trying to use the idea of cross-platform gaming to convince PC players to buy controllers; and, to a lesser extent, convince 360 gamers to buy those keyboard attachments for instant messaging. The whole concept may be little more than marketing slight-of-hand.