My only revolver is a 460 XVR. It has failed me twice:
1. Once, up north, I shot at a deer and the animal kept running.
2. Another time, I was sighting it in at 100 yards in preparation for deer hunting season. This was after several months of shooting smallbore and air rifle. My revolver jumped and the scope cut a semicircular incision on my forehead. Based on that amount of recoil, it should not have hit the X on the target but it did, making me question its accuracy.
I blame both incidents on the internal lock.
Seriously, I use my 1911s for concealed carry and I've found them to be extremely reliable as long as I use the correct ammunition, specific magazines (not just brand or type but actual units), and proper lubrication.
I've considered buying a 686 as a carry gun but that has been delayed indefinitely by budget priorities.
Based on what I've read in this thread, and on what I've been told in the past, a revolver malfunction, while improbable, could be difficult to resolve in the field. A semiautomatic malfunction can usually be cleared in seconds (depending on training and the type of malfunction, e.g., Type 1, 2, 3.).