I've been riding clipless for about 2 years. After I banged up my knee this spring I swapped out the clipless pedals and put on an old set of platforms just to try to see if my knee was ready to ride again. I rode the platforms for a couple of rides but ended up going back to my clipless pedals. I really prefer having my feet attached.
I just finished reading Grant Petersen's book as well. It was interesting. There was a lot that I agreed with but also a lot I didn't agree with. I think it's kind of like of like listening to your uncle, he spouts a lot of strange ideas but he has some real gems hidden in there with them and, you realize that he's probably forgotten more about bikes that I'll ever know.