Looking at the entire lines of those listed, I'd probably have to go Wilson, I've got Baers, a Wilson and a Nighthawk.
Have not yet had a Brown but plan on getting one sooner or later. I like Wilson's line-up and armor-tuff finish, Nighthawk is an off-shoot of Wilson, they said they could make a better gun for less, but they cost about the same or more. I think the Nighthawks are "prettier" than Wilsons, and I liked the fact that no matter what options I threw at the guy @ Nighthawk he just said "ok, we can do it"
As for Baers, most of their guns are blued, for a range gun or competition gun this is fine, but for carry I like something more corrosion resistant, both my Baers are DuPont S coated but that stuff aint' cheap, they are also very, very, tight when new, some are hard to cycle the slide one and most will require a bushing wrench. I bought both of mine used and they've been well broken in and perform flawlessly despite the tight tolerances (no sandy environment shooting for me) and they are tack drivers. My SRP needs a bushing wrench to take the gun down, my TRS does not.
Now as I said, that was looking at the entire line of those makers.
Each maker has models that are more preferred than others. Most Baers are a little less costly than the others listed, but are still fantastic guns, Browns have this understated classy look while Wilson and Nighthawk can tend to be a little over done. Baer doesn't offer a factory bobtail while the other three do. Nighthawks T3 is probably the finest "CCO" model available...
Either way you vote (or buy) it's hard to go wrong.