I'm in on the pre-order for the next batch of 81's - they've already taken my money (I ordered in January). Since ordering I emailed them to exchange my fixed stock option for a folding stock model, and they responded to that email quickly with a "No problem" and that was that. Being a pre-order, I didn't have a firm ETA date, nor did I expect one, and I'm far from being impatient about it.
Provided everything continues to go well, I will be happy with my dealings with them and wouldn't hesitate to buy again.