I'm 60 and have been riding Look pedals for about 4 years. I picked up some Speedplay Zero pedals in the spring of 2004. Whenever I had to stop for a traffic light and unclip I could never get clipped in again after the light changed. It took 3 or 4 attempts, so after a few months I gave up and went back to my beloved Look pedals.
I have EggBeaters on my commuter.
No knee problems for me.
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.