I am looking at the Williams wheels myself. Also, Neuvation
http://www.neuvationcycling.com/ has some good deals right now on "overstock" sets. He has all different sets; lightweight, stout and stiff, etc. And they have reviewed well and he stands behind them. For $300 or less, I'll probably got with them.
I can tell you that I have been running the American Classic Sprint 350s for 2 years now and I can't wait to get rid of them. Not stiff at all, go out of true pretty frequently,
squeaky as hell and the front rim has already had to be replaced under warranty. The only true redeeming quality of them is that they are very very light, but it heavily affects durability. I had to replace both front and back bearings sets after only 2000 miles because each right-side set was shot. Put some after market Boca bearings in and that seems to have solved bearing problem. Stay away from these wheels unless maybe you weigh 90 lbs and climb all day....