He really isn't though, watch him try to defend one on one.
I will say this, he's probably one of the top 5 help defenders for PGs in the league - but his defense is very overrated by Celtics fans.
As for the years argument, if they are putting up comparable numbers (and they are) when it's one player's first year in the league and another's third, it's pretty clear who the better player is, right?