Ya, UFC has never had a death, but keep in mind, they've only been around for a decade or so. Give it some time, it's bound to happen at some point.

Boxing is a dangerous sport, but I think it's gotten much safer over the past few decades. Watch a fight from the '50s, '60s, '70s, you'll see fighters who are completely out on their feet and defenseless, and the ref will let it keep going.

Back in the day, you basically had to go down for a 10 count for the fight to stop. I think most refs do a good job of stopping fights on time these days.