USB extension can be a bit of a nightmare. From my experience, there is not one cable that will just magically work reliably 100 out of 100 times. We certainly have ones that we have tested that seem to work better than others, but these are the ones that work the best out of what we have tested. We do still recommend getting a dedicated conference PC mounted behind your display, and then mounting the camera above or below the display and running the supplied USB cable to the conference PC. This will get rid of the need for USB extension at all which will make things far more reliable.
Siig USB 3.0/2.0 active extension cables. These seem to be very reliable, but they do fail to work sometimes. The main issue with this one as well as all active extensions in the heads are very large and running them through conduit is pretty much impossible without breaking the cables.
Icron Spectra USB 3.0 3001-15 (15 meter) active extension cable. I have tested this one pretty extensively and I have not had it fail on me. I have talked with customers who could not get it working though, so while extremely reliable, I can't say with 100% certainly it works 100 out of 100 times.
Icron Raven USB 3.0 extension (100 meter over cat 6a/7) This is a newer product on the market but it seems to be extremely well made. So far in our testing, we haven't had a single failure with this unit. The few clients that have used this have done so with success. The only downside to this extension is the price as it is the most expensive on this list.
Icron USB 2.0 Ranger 2301 (100 meter over cat5e/6/7). This unit has worked for us in the past, but I have talked with a few clients that could not get it working. So while it is a good unit, there are no guarantees.