Yes. RankerX is the best tool for Tier 1. But GSA is better option for Tier 3 or Tier 2Hands down GSA SER. Many recommends RankerX too. But IMO can do better for lower budgets with GSA SER.
Personally, I am using the GSA tool for tier building.i want to know what is What is the Best Tool For Tier 2 & 3