MIchael Jackson is clearly more famous. At least in Asia.
Elvis and Michael both may be equally famous in west but if you go somewhere in rural area of any Asian country you'll find people who knows Michael Jackson. Same can not be said for Elvis. In cities people may know Elvis but his songs are not popular. Michael's songs are. It's probably same in African countries.
My uncle who has never heard any English language song has heard Michael Jackson. I can find many people like him My grandma, she's 80+ and she doesn't know many local celebrities but she'd say "The guy who looks like girl." when you mention name 'Michael'. She hasn't heard any song (except when I play) but she knows him. I was surprised when I found out.
Michael Jacksons thriller album sold more than any of elvises albums. Michael Jacksons dances were learned world wide and still are, and Michael Jackson made more money and composed most of his songs and broke a lot more records. His death broke worldwide news and media tributes a lot more, and even Evis would agree that M. J definitely Rose to be more famous. Sorry Elvis, but facts are facts.
Of course Elvis. He's the king of rock n roll. He changed music with heart break hotel. Ignore the ones who were too young. They barely knew Jackson never mind elvis. Nobody in their day n age is anywhere near as big as those 2 were