My Santana came with wire bead 28c Gatorskins and after just over 2200 miles the rear looked worn enough to replace. Put on GP-4000's in 25c and took off over 100grams per tire. Gatorskins were bombproof but these have better ride, rollout. Even my wife noticed and she usually has no feel for changes.
I know these won't last as long and will be more flat prone but I think it's worth it, especially with the smooth usually clean roads here in SoCal.