Refactoring is a dream with JetBrains. But it is very language dependent, with Java having most support. Haven't used Kotlin in Intellij so I don't know how well Kotlin is supported, though I imagine rather well given that it their own language.
I use PyCharm and refactoring works pretty well there too. Also I really like having an IDE that runs and presents itself just the same on all big three platforms, since I'm always hopping between computers.
