Yeah, I have knee problems regardless of the pedal system. For commuting and touring I prefer sneakers and MKS Lambdas. My feet don't slip even in the rain unless I hit a big bump unexpectedly. It's just so nice to be able to hop off the bike and walk in comfortable shoes and to not deal with hauling another pair of non-bike shoes. On road and especially mountain day rides I like to clip in for better bike control. If I learned how to bunny hop with flat pedals I'd probably ditch clipless altogether.