Few Question about cocos creator & JSB

Hi, im new in js game development, im willing about learn creator, before that i have few question regarding basic stuff like :

  1. What is the best editor/IDE tool for creator where i can do auto correct & debugging easily in mac ?
  2. what is the purpose of JSB ?
  3. it said that JSB 2.0 is available, if using creator with js, do i still need JSB ? what is it has to do with performance ?