Well... I love the Shimano. Always works. Good for rough trail rides and stable enough for 100 mile road rides. Never had a problem clipping in or out. Never had to clean or service the pedals and any of my bikes. One benefit of the Shimano is adjustable release tension- loose, tight, or in between.

I have "heard" but not personally experienced that the beaters will get more loose after 1,000 miles or so and not be able to be tightened back up. The beaters look cooler and people will always ask you how you can stand on them... you'll get pretty funny reactions from non-bikers.