Except for the advanced metrics, Ginobili's stats have never blown anyone's socks off. Statwise, I'm thoroughly impressed Harden has put up his numbers on a team with Durant and Westbrook, which suspiciously looks like Ginobili putting up his numbers with Parker and Duncan when he came into the league.
The difference is Harden is putting up Ginobili numbers at a much younger age. His skillset is basically identical -- he can shoot, drive, pass, and take over the offense when needed. Separated from OKC's studs, I think it's crazy not to imagine his floor is Brandon Roy. And Brandon Roy with good knees is a Top 10 player in the game just like Harden is.
Practically speaking, a Harden deal is complicated by the fact that he needs to resign before you give up the store. But there's no question in my mind he's a MAX player.