The best part about using a mouse is quicker turning, honestly. It helps in any mode of play to be able to turn completely around instantly. Obviously, it's more helpful in match/ctf to have that ability, but there are times when playing single player where it can be very helpful, especially when trying to time attack. It does take a bit to get the hang of it, but I highly encourage you to give it a shot. I do agree, though, that the default mouse sensitivity is far too low. I play with the mouselook at the right end of the bar, but not beyond it (the mouselook actually keeps going off to the right beyond the end of the visible bar for some reason)