What do you want to do with the 4th axis?

Do you intend to use it as an indexing axis?

Or do you intend to rotary machine, such as a lathe operation?

I would recommend uccnc with a uc300eth motion controller.

Breakout board wise I use a ub1 from cncroom (Thailand). But can drive now offer the UCBB which is a lower cost option than the ub1 which offers a lot more)

http://cncdrive.com/UCBB.html

At the moment uccnc does not do rotary motion all axis are treated as linear.

Centroid I have never used, but I'd suggest asking a few questions on their forum and see what sort of a response you get (I asked a couple of questions and seemed to be given the short shift.... So I shifted onwards....). The acrorn seems reasonable, but the add-on software seems expensive as a package cost.

It also depends what you are using now or familiar with?

If you get annoyed with uccnc (not that I can see it) but you can flip back to mach3 or mach4 if you already have those licences at no cost