The indentations are made right, the pick can't rotate, move sideways, or fore and aft in the hand. Sound is the usual Ultex sound. The color makes it easier to spot on the ground if it falls. It feels grippy but not harsh. The sound might have a little more "chirpiness" than other Ultex picks, as Jeff Loomis says.
I use 1.14mm Ultex with all my axes but I recently got a metal axe with Floyd Rose and pickups that match the Duncan Distortion's very closely. So to balance the extra bass I play 1mm with that guitar exclusively.