His first stint was "unbelievable" for one season. Of those final three seasons, which were his most prolific at United, Rooney matched his goals in one of the seasons. Rooney throughout his career also outscored him in two more seasons than Ronnie's three "best".
Rudd Van Nistelrooy outscored him in 2 of the 3 "best Ronaldo seasons", as did Dwight Yorke. Best, Law, Charlton. I'm sure they'd have a thing to say about the other two seasons that Ronaldo had that apparently show his "legendary" status despite also doing the same. Hell, Rudd and Law have higher goalscoring numbers in a single season than Ronaldo's best year. But let's not forget that whilst Ronaldo was pumping these high numbers (and they are impressive but not exactly unheard of) he was also surrounded by a circus created by his people.
So in summary a player who was here for six seasons, had one season where he was incredibly prolific, which he capped off with the whole "slave" debacle, which is apparently enough to put him on the same pantheons as players who had better overall careers at the club statically and didn't leave a trail of shit and selfishness on their way to the next big paycheck. Nah, I'm really not buying the stuff about Ronaldo being a United legend because he had one amazing season.