Windows 7 Service Details
This service prioritizes user applications over background services. Great if you are running a desktop. Not great if you are running a server, and it puts higher priority on your 'desktop experience' while starving the background server apps you want to give priority to. It preloads applications that you most often use into memory as well, so it might end up using quite a bit of memory. I will get around to doing some in depth tests on this service later.
Maintains and improves system performance over time.
Consequences of Stopping:
Well, presumably your system would not improve over time. :) But, I cannot think of any reason to disable it. It is safe to do so, but it seems to be a beneficial service.
All services listed in 'Required For' will be unable to function