I have a Graphire 4, and it works fine for my purposes. I do mainly retouching, not a lot of "painting". Occasionally (maybe 1:100 PS sessions), I find photoshop stops responding to the pressure sensor, but restarting PS makes it work again. In terms of specs, it seems the Bamboo is very similar. As far as the size, I find it more than adequate for most work.
best regards, Darcy