I'm also in the market for a multi-purpose printer that is linux friendly, however I think my needs are a bit different than yours.
-I don't necessarily need laser functionality, but would be fine with monotone black only.
-I would prefer the printer not be overly large as I would like to hide it somewhere I don't have to stare at it.
-And would very much like wireless connectivity to be freed from the constraints locational placement.
-Toner/ink replacement needs to be reasonable cost.
-Linux friendly, of course.
I don't really have an opinion on your three choices because I've never used Samsung or Brother products, but thought I'd mention my needs in case they factor into your decision.