I just read personal reviews from people on roadbikereview.com that had their rims crack etc. from "normal use", and in short amounts of time. I also read that their hubs kind of suck in comparison to other companies, tend to blemish easily, and that they don't stand behind defects very well.

This is of course hearsay, but it does make me rethink Zipps a bit.

Not to say that they are all bad, but perhaps quality control is sub par.