They work well enough to a first approximation, but it's far from the certainty one has using other JetBrains products (e.g. C# ReSharper) on a statically typed codebase.

RubyMine will give you "Untyped (potential) usage." That's not good enough if I need to make a breaking API change and be sure that I've fixed all the callsites, such that I don't find out that I've missed a spot when the change breaks in production.

For all this talk about LLMs and AI improving developer productivity - what is one click and a few seconds in ReSharper to "Change Signature" or "Pull Members Up," which is a 100% guaranteed safe refactoring that will not introduce regressions, ends up being anywhere from "a few hours" of playing whack-a-mole with usage sites, to "completely intractable" in 15+ year old 1MLOC+ codebases making heavy use of metaprogramming.

If the Ruby milieu has turned against metaprogramming, I say good riddance; but my understanding is that it is still quite deep in technologies like Rails and RSpec in particular, where it's the fundamental secret sauce that enables convention-over-configuration and fluent, natural-language like DSLs.