I had PowerGrips for a short while on my new bike. When I bought it, I immediately installed toe cages because that's what I was used to, but quickly realized that they just weren't sufficient for the new bike. I wasn't yet ready to shell out the bucks for a clipless system, so I decided to try PowerGrips first.

In concept, they are great. Once they're adjusted for your foot size and you get used to them, they hold your foot very securely. And you have total control over foot placement. With your toes at an inward-pointing angle, you can insert your foot however far you want, then turn the toes straight ahead and you're strapped in. Getting out is also very easy, since the torque that holds you in disappears when you turn your toes in again.

I ended up trading mine in for clipless because I had trouble getting into them on the left side. It's possible that I had a defective strap, but when I would try to insert my toes the left strap would just push forward under my foot. When I went for a fitting and had to fiddle with the left one to be able to pedal on the trainer, I just said "Heck with it" and took the plunge for clipless. If you also get a defective strap or have any problems with installation, be sure to call the PowerGrip customer service people. They do seem to be very helpful (I had to get a replacement screw due to installation issues, but they sent it immediately with no questions asked).