I can vouch for Chaco's warranty. I had a pair of Z/1's and the footbed cracked out on them. I sent them in, and planned to pay for repairs, but about a week later a brand new pair showed up. In a better color as well.
I already owned a pair of Z/1 unaweep chaos in decent shape but i'v always wanted a pair of Z/2 chaos so i was able to get the Yampa ones.
My fiancée's pair just crapped out on her, she wore them to death, she had the pro soles and they don't seem to wear as well. Anyway i got her a pair of Z/2 unaweeps.