There may be a few Smart haters and Smart fanatics thrown in here and there, but I think most people generally agree on Marcus.
He is a solid passer, a very good defender, a high energy guy, and a leader with a penchant for big plays and clutch shots.
On the other hand, hes a miserable scorer and lacks the physical profile (not explosive, no natural elusiveness or handle) and natural scoring ability(touch, feel around the basket), and has a history of awful shot selection.
This lack of scoring ability and upside restricts what he can do for you but his leadership energy and defense make him a nice roleplayer.
Hes shown flashes of intelligent basketball that could make him much more valuable.
His ability to a. Improve his shooting and savvy around the basket and b. Play within his offense will determine whether he can be an elite role-player or a poor mans Tony Allen + point guard skills