Just my two coppers:

Mavic Ksyrium SL -- IMHO, the most over-bloated, over-priced wheel I have owned; multiple broken spokes and, most disturbingly, a cracked rim in multiple places after on a couple of years of exclusive road riding

Formula Xero XR-1 Wheelset -- no experience with these wheels

Williams System 30 -- I am into my second month of ownership of these wheels and they are by far my favorite that I have owned (and I have owned many); plus, Keith Williams, the owner, was amazing throughout the process (e.g., prompt, honest, thorough)

Neuvation M28 -- again, no experience here

Good luck