I know someone who swears by Speedplay. I on the other hand, have been using SPD-SL 105's for almost two years now. (with no lubing or tweaking after original setup).

The only thing thats worn down so far are my SIDI heels and screws that hold them in.

If you dont know which to go with, start with Shimano SPD-SL as your default. Then later you can experiment with all sorts of alternate systems that are out there.