I have a pair of ancient Shimano M505 pedals on my bike. They've seen duty on four different bikes, and I've owned them for over 7 years. In that time, I've never had to adjust them once, but they still work perfectly. The only issue about them is they are a little on the heavy side, but I'm not a weight weenie so I don't care. I'd definitely go with SPD again if I ever have to replace them - but I'd probably buy a pair of the double-sided pedals so I could ride my bike wearing regular shoes if I really wanted to.