I don't like 'em. On some lifts I feel like they artificially support your grip and on some I feel like they make it worse. For example, my tire for flipping is nasty-ass-filthy and gets your hands filthy when you touch it. So my buddy tries to wear gloves to flip it. Now, mind you, he's not a big guy and his hand strength is nothing to write home about, but normally he can at least flip the damn thing. Not with gloves, couldn't even budge it.. No traction... Now, on something like a rack pull, I feel like the bar "bites" into the gloves and helps your grip. I might be wrong, as it's been months since I've worn gloves to lift.
Here's a thread about rips:
I use the pumice stone to keep 'em worked down. You want them thick, but not bumpy with sharp ridges, that's how you rip 'em off.
Also, I would only use the pumice stone and then some kind of lotion AFTER your work out, like maybe before you go to sleep.
Hope that helps.