IMO inertia single triggers are easier to diagnose and fix, when they're not working properly, than mechanical ones. Maybe it's just the way my brain works but I can understand inertia triggers better than I can mechanical ones.
I fixed a Beretta Silver Snipe single trigger some months ago for a friend. I cleaned it in the ultrasonic then lubed it carefully with a thin oil. He said it worked a few shots then stopped working. I agreed to look at it again, puzzled. I found that the inertia block, the swinging weight which moves in relation to the recoil, was swinging on a pin which was actually a screw which could be tightened or loosened. I determined that it was a tiny bit too tight which was creating a "drag" on the weight as it tried to swing freely. I loosened that tiny screw just a bit and everything has worked fine since.
I'm a mechanical/technical junkie. I love figuring out and understanding mechanisms. Because of this I am a big fan of selective ejectors on break open guns. When they're right they are a sheer joy to me. Triggers are, too. My first love is double triggers. But I will not write a gun off completely solely because it has a single trigger. I have numerous ones. All mine work perfectly. I have had one HOT double on me, but I have determined that it was operator error, not the trigger itself. My pre-'13 LC Smith grade 3 has a HOT. It was originally a pigeon gun, with 3" chambers and 32" barrels. I used it with 1 1/4 oz. handloads of bismuth, and it doubled on me. There are two kinds of doubling. One is where the trigger messes up and causes the doubling. The other is caused by the shooter, when the recoil causes him to hit the trigger twice, the second time because of the recoil. This is what happened to me. It has never doubled with 1 1/8 oz., or less, loads, only with heavy duck loads.
Maybe part of the blame that single selective triggers receive isn't the trigger's fault at all, but the shooter's. Either way, I agree that double triggers are preferred .......... most of the time.