I am "demo"ing a set of Zipp 404's. The shop has offered me to purchase these demo's for half price (2011). The front wheel is rebuilt and the back wheel has clearly been used. Is it worth purchasing these or should I just spring the $$ and buy new. The performance of these wheels is clearly better than my shimanos.
Advise?

"The performance of these wheels is clearly better than my shimanos"

ha^

buy new - why risk a failure from a wheel that was abused as a demo - think of it like a rental car - would you buy one even at half price?

i've bought several used carbon wheels and all have performed better than expected. A set of 2000 dollars wheel for half off- hell yeah i'd buy them. Plus if a shop has them just ask they be checked for trueness and ask to have the wheels tuned up.