Be prepared to tighten up the pivot points. Both rivet and getting a better match between the folded body and pivoting component in between. Often the body fold isn't perfectly parallel so the in between part only touches at the outer edge. Not good for stability. Take a good look at the one for the long jaw. Any slackness and such devices can be worryingly floppy. Enough to reduce the grip or make it likely to slide sideways.
I've not had experience with those particular devices and brands but all the inexpensive "modified jaw" Mole style locking wrench devices I've had through my hands got some attention. As received quality has varied from "so floppy that the jaws slide past each other when loaded", a small extended jaw version out of a LiDL three pack, to "works well enough that normal folk will be happy but I want it right", the big one out of that same LiDL pack.
Usually as delivered quality is in the OK(ish) to adequately functional range so they can be used straight out of the box but might need a bit of extra care, skilled tweaking or whatever under some circumstances. Bit of a faff making up devices to tighten the pivots but, in my view worth it. That clamp arm is a long way from its pivot! Firming up the pivots improves the locking action too. A forked welding clamp version was very squidgy and imprecise when locking as delivered. The business end was wonderfully firm tho'.
No need to overdo things. Generally only a little nip does the deed. Given the price differential between the inexpensive versions and the professional ones there is no way I'm complaining about doing a bit of tweaking. Especially as I rarely use any of my collection. But when I need them I need them.
Clive