Why Is It?

I never have used MSD but I watch the RoadKill guys hit the highway with at least 3 spare MSD everything!!
I have an MSD 6AL in both of my trucks, and I haven't had a lick of trouble with either of them. (OEM distributors, though.)

But like you I've seen the knuckleheads on Roadkill have troubles with 'em, so I bought a spare/back-up 6AL, and a coil, a couple years ago, just in case.