ivancarlos said:
my opinion based on experience of having tried them, is that they're an absolute pile of shite. Fine once you're in, but they're far too difficult to clip into, and far to easy to slip off the pedal if you don't clip in first time. As are time atacs, although not quite as bad as eggbeaters. Shimano pedals feel like they actually WANT you to clip into them, mine feel like they're just drawing your foot towards the clip in zone so much so that they're a joy to use.
Personally I recommend M647 (DX) ones, they're of a mud shedding design (unlike say M424)