In my experience ZT's quality has been far more consistent than BM, which seems to be hit or miss lately. I think KIA is really trying hard right now to be at the top of it's game, BM not so much. I'm really not the biggest flipper fan (or bearings for that matter), but the 0562cf, 0452cf, and 0801 are all different flavors of perfection IMO.
I have had more than a few Benchmades, and most of them had an issue of some kind, even if it is a small one. I took delivery of two 555-1's recently, one had above average axis lock blade play, the other was quite off center. Still enjoy carrying a 555, 940, or 484 quite a bit though.
Both ZT and BM have been unbelievable when it comes to great customer service.