triple foam brush...pros/cons/best color combination?

[trs246810]

I've searched old threads...and have seen some discussion on these units...mostly just opinions of some of the companies that manufacture these units, but not much as to the pros and cons of running triple foam to the foamy brush. Also, for those who run triple foam...which I'm about to install...what have you found to be the most appealing color combination? I just bought a new Dilling Harris unit on eBay. It's the add on two tank unit that will work in combination with my currently running single color pink.