I have the apple bluetooth mouse - very responsive, nice feel, but I cannot live without a multibutton mouse (mostly to map expose commands).
Bought Microsoft BT mouse - its ok, but I find it has just that little bit of delay or lag. Not major - but enough that I don't want to use it.
I have thought about trying the logitexh mx 900, but the lack of native drivers made me worry that it would be as laggy as the MS mouse.
For my desktops, despite the inelegance of an extra peripheral plugged into the computer, I have gone with the logitech mx 1000. Great mouse.