The zip tie used to keep the carabiner's strap-lock from falling apart is sloppy. Not only aesthetically, but the sliding bar can slide around and get wedged into paces that makes the device trickier to work with than one might expect. This is especially the case when under load.
The other issue is that the opening of the carabiner is narrow--it's a 12mm opening if you completely compress the latch. And when you press the latch down, your finger takes up some of the 12mm space and gets in the way of whatever you are releasing.
They system does work as a suspension system--it's never slipped, and I've never fallen out of a tree--so that's great. Still, there appears to be considerable room for improvement on the carabiner side.