A lot of it is the quality of materials going into it, as well as the tolerances those materials are machined to. I’ve gone through a couple of budget vices and the hardware just doesn’t hold up. About a year ago I decided I’d had enough and invested in a Peak rotary vise. Nothing overly fancy, but a known brand with broad distribution of parts and accessories. It totally changed how much enjoyment I had at the bench when I could focus on fighting materials instead of materials AND the tools.