I have a pair of ZF1's and my experience has been positive.
When I first got them, the skate cuff was pinching a nerve in my foot (very, very isolated issue), but now that they've packed out somewhat, it doesnt happen anymore. I've also shredded one of the outer-laces after about 10 days, due to a defective lace-tightening mechanism; the internal metal piece exposed itself and shredded the lace. Good thing they came with backups.
This will be my 3rd season on them, but the last two seasons, I've only been out about 15 times each, so max of maybe 30-ish days. Used for everything: park, trees, back-country hiking, etc. My only real complaint is that they're not the warmest boots ever, but staying warm isn't too much of an issue for me.
For the price, I absolutely love them.