To OP: I don't think you'll go seriously wrong either way. I have an old pair of 520's on my commute bike and they are just fine, no issues, easy to snap into or clip out of; spin freely with zero maintenence.

By the same token (pretty much), I think you would be happy with the Crank Bros. Egg Beaters. I use them on my fixed gear bike just because the 4-sided-ness makes them an easy (albeit moving) target when clicking in. Again though, no problem snapping in or clicking out and no problems even with zero maintenence.

Rick / OCRR