I've had the 5" raptors for 4 years now and haven't had any problems. Very happy with them. Nice thing about them is the ends are sealed and polished, no plastic inserts to fall off. The only issue i have notice since they have gotten older is the pad sometimes rises a little bit in the front, 1/4 inch, so I just press it down, not a big deal to me.
I got the 5" since I figured the 4" would look to small and I had less chance of slipping off. Also for my wife since she has a bad back the wider step makes it a little easier for her.