I bought a Chinesium angle-lock type (Kurt clone) vise some years ago and it was pretty crap, rather like you describe. Finally I dismantled it and was surprised at what I found, even though I had low expectations. The angled face on the moving jaw was so roughly finished that the contact between it and the nut was made on the casting mould line. The half spherical seating (aka ground down ball bearing) that is supposed to form the contact was in fact present - but it was lurking in the background as a sort of lucky charm I guess. It was only retained by the heavy grease that had also ended up in there somehow.

I machined a proper spherical seating for the ball bearing using a 16mm ball end mill (ironically from Arc Euro) and reassembled it, thus sort of regaining some of the intended function. However by this time it was somewhat weakened. I use it on my smaller machine now but I was fully aware that I'd been polishing a turd.

For my main machine, I have one of Arc Euro's 160mm versatile vises and it's pretty satisfactory. Ketan at Arc has got his supplier quality control fairly well sussed.

A half decent angle lock vise will resist jaw lift but there are probably instances where the concept can't work. However, I've not encountered any so far with the Arc Euro one. I'd certainly recommend one from my own experience and understanding.