Lots of "Pep vs Sadler" debate - but that isn't what the thread is about, it's about who was the closest to "unbeatable" (obviously no boxer is totally unbeatable, but you know what I mean). IMO Pep was harder to beat for most fighters than Sadler was. If I was a contender in that era, and had to win, I'd rather be against Sadler than Pep, that's for sure.