if the camera was working, cm9 would've been the best piece of software for our device
GPS (from cold) locks in 2 seconds, to 7-8 satellites at least, furthermore, it even locks if u are not in the open, with samsung stock roms it seemed like the gps antenna on i9001 is very weak, i never could get a lock while i'm in the apartment (8th floor in a 10 floor building), i had to stick my hand out of the window and wait for a few minutes. with cm9 i get a lock within 5-10 seconds while i'm inside the apartment.
battery life? 1 day 13h still have 37% left, and i've used my phone a lot, watched youtube, surfed, read xda a lot, wifi always ON, few sms... the only hint for that is that u have to have a caliberated battery.
wifi shows lower signal than on stock roms (in terms of bars u see in the icon), but speed is not affected, so it might well be only visual.
RAM management is the killer part, i never got over 250 mb of used RAM, and i have all sort of apps running, whatsapp, viber, facebook,elixir... and all of them take it's share. with cm9 u get 370mb of free RAM (at least for now).
smoothness and very rare wake lag are also important factors that talk in cm9's favor.
there are still some bugs in cm9, no one is ignoring that, but in my opinion it's already (by far) better than stock, camera is the only limiting factor (and actually i usually use it quite frequently) , other than that KQB is no where in the rank of cm9