Shimano RS-10s are garbage.

So were the R-500s that they replaced, and currently exist alongside of.

My riding buddy broke 4 spokes in the first month of riding. After I fixed the LBSs poor repair jobs and properly re-tensioned the wheel, it managed to finally go 200 miles before throwing another spoke. My buddy is currently riding a set of 105/Mavic CXP-22/DT Competition wheels that I built and have loaned him while he works on warranteeing and then unloading the garbage RS-10s.

My 105/CXP-22 wheels I believe are lighter. And he took them to RAGBRAI where they did fine. I've advised him to go Open Pro/Ultegra, or if he wants low spoke count to look into Ksyrium Equipes.