Im using a full Nikon system too xD haha I have like 2 lenses only does that count?anyway it neatly fills in my midrange lens gap that I have. Nicely compliments my DSLR set up too. AF isnt really that slow. Slow to those who are pampered by ultrasonic motors but most definitely not slow. It would be a nice addition to anyone's area email really.
You still have your Nikon system with you? How long did you have XP1? Please update the usage/fequency usage of both system...