Dang, I haven't posted here in a long time.
I had a Zero 1 TC (tactical compact). Recently sold it -- will get to why.
I bought it because I was specifically looking for an optics ready DA/SA gun for less than $1000. Not too many options there at the time.
Was impressed with the build quality. Machining was clean, good fitment, etc. Optics plates are metal and solid. It was always reliable.
Trigger was not great. The DA weight exceeded the range of my trigger pull gauge. I'd estimate it was 13 lbs. I don't normally mind a heavy trigger, but this was heavy enough to cause fatigue after a little bit of practicing. SA was 8 lbs. I replaced the hammer spring with the Arex competition spring, which took the weight down to about 8/4.5.
The grip was my biggest problem. I have small hands and it is large, but not so large I couldn't handle it. I would say it felt something like a 92FS. Maybe a bit fatter. But it's also a short grip. You've got a small amount of vertical real estate (from the bottom of the trigger guard to the magazine). It's only about as much as a Sig P365, and maybe a bit less. I guess this could be fixed by going with a standard size model. The factory grips are also slippery plastic and I would recommend changing those out.
The slide stop was always stiff and I had no hope of pushing it down with my shooting hand without adjusting my grip.
They are good guns if you can deal with these quirks.