Is there some official standard for how much better someone has to be to be considered on another "level" that I'm not aware of? Is Mir on the same level as say, JDS? You could argue that they are, both are UFC championship level. Of course, then I could argue that they aren't, as JDS has a much better record overall, including against common opponents, and beat down Mir when they fought. I guess you could argue that not only are both of them on the same level, but so is say, Christian Morecraft...UFC level, or pro-mma level. In that sense you'd be correct, at least technically.
Again though, if you'd followed their careers we wouldn't even be discussing this. Roger is like the Michael Phelps of BJJ, the Lance Armstrong without the steroids. His medal chest is full of gold from almost every tournament he ever entered. Jacare's career was going similarly but he retired early...he won gold in very nearly every tournament he entered, with only a very few exceptions where he got silver.
Maia, on the other hand, is a guy who was competitive at the top level, but rarely won. He has a few good wins with ADCC being his best, but he likely only even won that because Jacare didn't compete that year, as Jacare easily beat Maia in the finals of the previous ADCC. Most of his medals are bronze and a few silver though, and he even entered some tournaments where he didn't even medal.
The fact of the matter is, Roger and Jacare are frequently talked about as among the best BJJ practitioners of all time, and rightly so. Their names in BJJ are comparable to the GSP's, Fedor's and Anderson Silva's of MMA. Maia is that guy that had a few good wins, a handful of losses to tough guys, and won a title during a weak period but never defended it. Like Forrest Griffin, perhaps? Nah, he's better than Forrest, but you get the idea. If that's not two different levels, then I don't know what is.
