Like another reviewer mentioned, I found the USB-C connector does not fit sung into the port. The USB-B side of the cable connects with devices securely but the USB-C side seems like it's manufactured slightly too small. I tested the connection on three USB-C / Thunderbolt 3 devices - Late 2016 Apple Macbook Pro, HP Elitebook Folio G1 and a HP ZBook Studio. G3. The connection isn't as secure as I would like on any of these devices. The connection is more secure on the HP devices compared to the Macbook Pro but it's still not what I would call a firm connection. I also tested the connection on an HP Thunderbolt 3 docking station and there it does seem secure.
This seems to just come down to manufacturing tolerances but I'm not comfortable using these with the latest Apple Macbook Pro. An accidental disconnect from and external drive seems too likely.
The cable works perfectly for my usb 3.0 hub. The only gripe is that the usb c connector is looser than I would have liked. It still clicks in place, and doesn't come off easily, but it has much more wiggle room than the ones bought from Apple.