Falcon 9 has a very good track record. They lost one on the pad and one in-flight... that's out of 80-some commercial missions. Refurbished boosters are not yet man-rated, but the boosters used to launch crews to the ISS can still be used again for commercial launches, so there is still a significant cost saving. No fire in Mercury... that was Apollo-1 The potentially serious Mercury issue was when Grissom's hatch blew after splashdown, flooding the spacecraft. As with Apollo 13... timing of that accident was everything. A few moments earlier and he would have gone down with the ship, and a few moments later and it could have killed one of the frogmen securing the craft.