I just installed M530's on my Trek FX and it is the best upgrade I could have ever done to this bike. Mind you this is my first experience with clipless pedals, and now, I can never imagine going back to flats. Even just cruising, let alone fitness training, it is so much more efficient, and safe, imo. Have not fallen yet, and to be honest, I can't see how you would, as long as you remain vigilant. SPD's are so easy to clip in and out.

So in retrospect, I wish I had gone with M520's or other double sided pedal.