I wear Specialized MTBs with a recessed cleat and love them. The only problem I had the first week I wore them was on the inside of my Achilles Tendon area - which I knew was due to the way the cleat held my foot on the pedal. Since that first week I haven't had any problems and Love the power I can get from push/pull pedaling!
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"