Fast, good, cheap.
You can't have all this.
My experience is that the best gunsmiths charge the same as poor gunsmiths, but the turn-around is agonizingly slow with good 'smiths. Naturally, everybody wants the best and most are willing to wait for it.
You'll get lots of opinions, because there are more than a couple of good gunsmiths.
The best set of Rugers I have were done by Bob James.
However, sometimes putting a hammer in a Ruger is just a bolt-up affair. You can easily do it yourself by following the video on the Ruger website. It might work without any "gunsmithing."