The systems are time-tested. How many accidental launches have happened so far? Zero. In my opinion that's the most important metric of these systems, as long as they are still credible threats otherwise.

Also, what could a better system improve? Slightly faster launches? Slightly more certain launches? I argue that those are not important -- the enemy won't fear the missiles more if they run off USB. But you might increase the chance of a false launch, and certainly incur large testing costs.