Well like mentioned earlier. If you will be climbing a fair bit, want the newest version and an anal retentive build towards quality go with the 38's you won't be disappointed. If you want last version, slight bit better (perhaps) at higher speeds and still anal retentive quality build then go 50. Will these be you regular wheels or just using for races/tri's?
I went from 60 to 52, and now with 38s, I'm insanely happy. I'm 165, but found myself thrown around more than I'd like on windy days. I love my 38s!
Right, those were two separate thoughts, sorry that wasn't clear. This year, I'll be running these wheels as an all-purpose set as well as racing on them. Next year, I'll likely not be using them for racing (hence the tacked on comment regarding a tri bike).
That's the tentative plan!
38, because of cross winds.
Don't believe everything you think.