UFC & Pride is not safer than boxing! repeated knees, elbows to the head until the opponent is knocked out? check silva vs quintin jackson. in Pride you can kick them on the head while the opponents on the floor! In boxing or K-1 once the opponent falls down the judge gets in the way and lets him get up. In ufc, as soon as your opponent is down, you pound on them for a knockout.
but even then i think ufc is a sport that requires enormous amount of skills, because those athletes have to be able to counter any style of fighting, and at the end of the fight they always have respect for the opponent. the ufc is well regulated, so their fighters do it for the sport. the less regulated tournaments that occur can involve criminal fighters.
just saw this: South Korea boxer dies after bout
http://news.bbc.co.uk/sport1/hi/boxing/7167435.stm
i think in ufc the gloves that they wear has far less padding than boxing gloves.