Given the choice of a pit that came with a mediocre coach vs. a pretty good coach...... the pretty good coach is the way to go, because kids can still get hurt if they're using a pit under the supervision of a coach, and are far, far more likely to get hurt if the coach doesn't have experience enough to know the hazards involved with pit use.
Having said that, the better situation is to have a pretty good coach and a pit, because there are skills too complex that travel too far, too fast, or too high for me to be in the right place at the right time. Accidents happen, and they can originate with the coach catching a toe on the carpet or the kid traveling farther than ever and exceeding the boundary of the safety matting. That's going to end up with a coach desperately side stepping on a squishy matting to catch up with the athlete. Sure, that kinda stuff mostly happens in nightmares and very rarely in reality, but when it does the result is rarely an experience anyone would ever want to repeat.
I guess the bottom line is that I would have to cut back on some of the skills I'd have kids working, and spend more time running for ice packs (no, not for the kids.... for me), and coach a few less kids.