Its certainly not QD fast, but I takes a whole whopping 20 seconds to put on. I haven't had any issues of loosening. I put nickel never-seize on the threads outta habit, so no issue of it getting frozen.
A huge plus for me is the 16" middy is a BCM lightweight, and I could tell the difference with just the YHM mount on it. Now with just an A2, it balances so much better.
So far I have mounted it to BCM 11.5", BCM 16" lightweight, and YHM 20" diamond flued HBAR with no issues. Naturaly the 20" is the most pleasant to shoot. The 11.5" is no longer ear shattering loud.
For the price I paid ($450ish iirc) I have no complaints.