I use one, the portable 12w.
Good things with FCP: works as a second monitor for my laptop; is very, very useful in Motion; makes for an interesting way to do complex audio mixes (put nothing but the mixer on the tablet); when you've been working long hours, and you want to lay back and continue to work in a more restful position, it goes great on your lap; if you are assembling a cut down or nuggets reel, the pen works mighty fast in combination with the Blade tool; the ten tablet buttons can be assigned presets for FCP, so that it becomes a pretty good controller, too.
Not so good things: Only two things, really; 1) I like using pen and mouse alternatively, and, unlike other Waccoms, it does not take a mouse, 2) I would like to use it more often with my Mac Pro, but I also like dual monitors, so FCP's dual monitor limitation keeps me from installing a second video card.
