I went from spd/platform (same pedal) to MKS touring pedals. I could never get the spd's dialed in where my knees did not hurt or my feet had issues w/numbness, hot spots etc. I went through 3 pairs of shoes and one pair of sandals, adjusted my saddle up down back & forth etc.

The thing I noticed on the first ride with the platforms was how much I moved my foot around while riding. I was always moving my foot for and aft and in and out. I am not a performace oriented rider and average 13-14mph on my commute (30m RT). I can say that I have had not comfort issues of any kind since switching over to platforms. I do miss the feeling of security of being attached to the bike, especially in the the big rainstorn I rode through last week. That said, I just slowed down a bit and was able to pedal with no problems. YMMV