I'm still using a Rival 300, but it's wearing down.
I wish I could find a mouse that has room for my ring finger to rest on top. My thumb, index, and middle finger have a palm grip but my ring and pinky use a claw or just drag on the mousepad. Every mouse I've tried is too small except the vertical Logitech one designed around having all four fingers on it, but I don't like that position.