I saw that the other day. Xbox360fanboy had a pretty decent sized review of it and needless to say, they weren't very impressed.
Original xbox had something similiar (forgot what it was called) that I've read worked suprisingly well, especially given that all xbox games never took into account possibly even supporting mouse/keyboard somewhere down the road.
While I still prefer mouse and keyboard I can see why a lot of people are against it, it simply makes the game (FPS's in particular) unfair to those with controllers..
Back in the dreamcast days I hooked up the DC mouse/keyboard and slaughtered everyone in quake 3 and unreal tournament!
(And the DC game pad didn't even have dual analog control)
Got used to the xbox/360 controller as well.. they definitely have the best one (IMO) of all the consoles when it comes to controlling FPS's.
Now we just have to wait and see how cross-platform (360 vs Vista) titles like Shadowrun play when some have controllers and others have mouse/keyboard. Should be interesting to see as the developer keeps touting they are making it fair for all players regardless of platform.