It's hard to say this about any ballplayer, but he's both underrated and overrated. Why? Simple.
For all the Gold Gloves he won (five), there is advanced baseball metrics that peg him as a subpar defensive shortstop his entire career, that the awards he won were not deserved. In that respect, his greatness defensively is way overrated.
He is widely underrated in that offensively, the numbers he was able to compile while playing probably the most demanding position on the infield, in a market where his every move is micro analyzed, it just beyond impressive. He was a clean player in an era where many players were taking PED's, and was a class act on and off the field. Young kids coming up through the baseball system should look at him as an example on how to play the game the right way.
All that said, he's a first ballot Hall of Famer and Cooperstown is going to be jammed with Yankee fans in 2020.