How peeps can say Biggie 'n even Pac are/were overated is fuckin beyond me... Two different styles that made most artists up their own game... not to mention the classics they dropped themselves...
They're overated in the sense that all bubblegum/50 rap fans d/r their shit, but damn....still unmatched.....
Nas also...practically every album's been quality in my eyes...

50 Cent - Most overated by far...
G-Unit/Obie Trice - Them too...
Jay Z - Personally I think he's wack...

As said...most mainstream artists I guess....