I’ve been looking at Q as well and I’m impressed so far. It was pointed out to me by a guy who developed it called Servan (didn’t catch his last name) at the Bernie Stolar thing in Enterprise Ireland. He also co-developed the original Direct3D, so he knows what he’s talking about.
The most attrative thing about it, once you get past all the standard technical features is the licencing. It’s a free Windows licence but you have to pay for Playstation or XBox which are both supported. Theoretically, this makes it easy for a guerrilla developer to create a game under less stressful circumstances that’s ready for porting if it’s a success. (And made with porting in mind, of course).