[alf]

From my personal experience, the best non-govt sponsored martial arts instructors teach non-profit. When people teach MA for a living, compromises are made. Look into Kendo and Judo, those are pretty much the only 2 big MAs in the US that are still non profit. Community centers also tend to have non-profit instructors. You could figure it out pretty quick when you find out that they have real day jobs.

Find a good instructor, that is more important than the style/art.

Edit: Kendo and Judo instructors will not usually take 3YOs. that is too young to start MA in a formal setting. But if the MA teacher is doing it for profit they most likely will make the compromise.