I've had 2 Limbdrivers already,(Still have 1)and I do like the concept but I HAVE seen the cord stretch a bit (As evidenced by the launcher slowly lifting off the shelf while the bow is at rest over time. The launcher starts flush to the shelf and after a bunch of shots I've seen it as much as 1/8" off. This will not affect the amount that the rest can come up changing the initial launch angle but it should or could possibly affect the timing of how it is pulled down out of the way.
It's details I know, and I do like the rest, however the string loop material cord is the reason why I am braiding a custom cord out of kevlar fly tying thread.

Trust me if it's good enough for Tim Gillingham it's good enough for me, I just want to refine the thing and or possibly pick up one of the new models. Things that can possibly move at varying rates make me nervous.