I switched from some old SPDs to these just recently and they are Great. Easy in easy out. I never feel like I am completely locked into the pedal so the fear of not being to get out in time is never in my mind.
There are two settings when you set up the cleats for how much you have to turn your foot to release from the pedal. I chose the lower setting so that I can get out quickly when needed. No pre-releases yet. The higher setting requires quite a bit more roation.