I spoke to two guys I know with thousands of GA SEP hours. One, with 3,000 hours, has never had an engine failure (and he's an instructor, ref previous comments about the reliability of flying school rentals) and the other with 6,000 hours (private flying) has had one engine failure. The latter also commented that engines rarely just stop, there is usually a warning that all is not well (gauges, strange noises etc). And hopefully the pilot is paying attention and spots the warning signs before the thing goes bang...