ZT was good to me about replacing a totdtor bar, but that was five years ago. Benchmade was terrible to work with. Spyderco has been the best. Though I've only ordered new screws and a g-clip.
I would buy the ZT, but not necessarily that model. I've had several, but my favorite and only one is an 0095BLK. My only CS experience was good. I bought a used, deassisted 0350 as my first ZT, and they hooked me up no problem. Same with one that broke in my blur. Fit and finish has been good with every knife I've owned; Kai, Kershaw, and ZT.
I had an acquaintance who swore by his Microtechs. Then one of his OTFs broke, wouldn't open. 3 weeks to get a callback. Two months before he got it back. Last I heard he sold all his MT's.
I no longer buy assisted knives, and have never owned an auto. But based on my experience, ZT is a better bet. KAI generally puts out quality products. I've owned 3 Kershaw's, 6 ZT's, and a KAI kitchen knife.