Marcus Smart. Rarely saw any PG with that combination of strength, length and defensive IQ. But his competitiveness makes it #1 on my fav Celtic list of today. Love when he battles against players from the size of Russell Westbrook, to Leonard/Lebron to Porzingis (he gives up about 1' of size.
P.S. In the match against the Lakers in December, I never saw Kobe Bryant struggle to post up someone like he did with Smart.