Howdy. I've used Powergrips + MKS Touring Pedals with Keens and thought they were alright. I found that I had to use the extra long Powergrips because the toe box on Keens are so wide and they were tough to get into the regular length ones.
In the end, I tossed the Powergrips. We ride with MKS GripKings that have spikes in them and love them. I think any BMX type pedal with traction pins would work great with Keens. The spikes/pins give enough traction so you don't slip off the pedals when it is wet. Our bikes are around 140lbs, so it seems that any retention system has diminishing returns with all our weight.
Russ
www.pathlesspedaled.com
www.epicureancyclist.com
GripKing with spikes reviewed here:
http://epicureancyclist.com/?p=868
