If I were to rank the d right now by how well they've played in the playoffs:
1. McDonagh
2. Girardi
3. Stralman
4. Moore
5. Del Zotto
6. Eminger
Girardi and Stralman are close but I'd give Girardi the nod as he usually takes more minutes and gets the more challenging assignments. Del Zotto's defense has been iffy throughout.
Del Zotto IMO is going to be a very good player but I don't see him ever becoming a legitimate No. 1 d-man. He's a 40-45 point guy with decent defensive ability. He's not particularly big or strong, his skating is not elite and his shot is average. He has very good offensive instincts but the tools--skating and shot are going to limit his offensive production--not to mention Tortorella's defense first system. The Rangers could use another offensive defenseman who at least has some of the tools that MDZ lacks. Maybe they could get more out of Moore. They could also use a legit 1st line center--questionable whether Stepan or Brassard can fill that position.