This is the device that I alluded to in another thread a few days ago. It is terrible as a WebCam, for exactly the reason that @RoGeorge gives. Using its own screen, however, the latency is negligible, just as with the LCD screen in a typical digital camera.
The mount is not as rigid as I would like, and for soldering it allows only 2 or 3 cm of working distance. The optics, however, allow focusing at much greater distances, so the real question is how much of the supplied mount should be retained in constructing one's own fixture. Because one looks at a screen, rather than through eyepieces, one won't be touching the device while using it, so rigidity is a little less of an issue than it might be. The device wiggles while one is turning the knob to focus it, and that is a bit of a PITA, but in use it's OK.
I built my fixture (pictured in the earlier thread) of 0.5-inch O-1 steel and a 3-cm cube of aluminum.
I was prepared to ditch the suction-cup base, for the reason that @Avacee gives, but it turns out to be solid when applied to a smooth metal surface. In fact, it's hard to remove.
In my experience, the main problem with it is that even though it lets me see what my tools are doing very well, I have trouble moving them smoothly when I'm looking in any direction other than straight at them. I don't have enough experience with the device yet to know if I will adapt to this. With luck, I'll adapt to it as dentists adapt to mirrors, or as orthopedists adapt to arthroscopes.