550 can be found on Performance or Nashbar for mid/upper $100's and even cheaper on ebay.
I've put about 1200 miles on mine with the last 200 on my CX bike. Only recently broke a spoke due to CX abuse. From a performance standpoint, these wheels "feel" sluggish compared to other wheels I've rode (Kysrium Elites/SSL, Easton Circuits, Nuevations, AC 350, OP/Ultegra).
If it's not that much extra, swap them out for a mid range wheelset.