I have been trying out Flock. And while it’s very pretty, and actually very functional. On my old iMac (800Mhz, 512GB flat-panel) it’s to say the least, Glacial. Smooth, but Glacial.
Update: I have tried it out on my iBook (500Mhz G3) and the performance is almost the same as on the faster iMac platform.
Donncha Thinks differently Flocking Fast