They were both good in their day - it doesn't matter who was better.
Dorian won eveything he needed to when he was competing. And won four of his Olympias with a torn bicep. And against the cream of the crop of the day - Flex, Shawn, Kevin, Nasser etc. He never lost a contest from 1992 onwards.
Ronnie at his best was probably the freakiest bodybuilder in history and none of his competitiors came close to beating him in his finest years - the year he came in at 290lbs+ contest shape ripped to the bone I don't think will ever be beaten. Ronnie lacked calves and decent abs but like Dorian, no-one really came close. His only major slip-ups were a defeat to Gunter whilst still Mr Olympia, and losing the crown to Jay. He wasn't complete enough to win the Olympia with a torn muscle, unlike Dorian.
So can we now all shut the fuck up and concentrate on bringing Mars and Squadfather back?