I've made a fair number of them. When it first came out there was some concern about the sturdiness of the clip (it just hooks into two holes in the body). So far, I've had no returns from the few I've sold and no failures of the ones LOML has (2).
The mechanism is a bit quieter than the "Clicker" from CSUSA (which I think is rather loud and "raspy" - but seems robust) but not as quiet and silky smooth as, say, the Vertex (from PSI).
I don't know about the "Zebra" refill, but I don't see why you couldn't shorten the tube for a shorter refill - there's nothing inside it.