I would agree, and add in that a proper bike fit will help you immensely. Personally, I run SPD's on all of my bikes, so I am used to them already. The feel and amount of float that they offer along with a good cleat setup allows me to ride anywhere from 50-100 miles on any of my bikes with no knee pain. If you are smart about it, there should be no reason that you can't get back on a fixed gear again.