Inversely; I have the wireless bigger-brother to Sloth's mouse and I'm using a palm-grip on it. Albeit a weird one. (More on that later), expanding the mouse back and placing the taller palm-rest on it made it so much more comfortable to use, it's possibly more comfortable than my previous X748K. My palm grip is so wierd because I don't move my hand to move the mouse. At 5600 (And 3200, to an extent.), you don't actually have to move your whole hand, just slide the mouse a little underneath your palm and you're where you want to be most times. I'll still rest my palm on it while I do this, however, so I don't get very far before i have to my my hand, but it's still comfortable to use for me. I suppose this is a weird hybrid between palm and fingertip grips.