As it applies to semi-customs, brand loyalty will quickly devolve into a Coke vs. Pepsi discussion. All have their pros and cons, but ultimately the best pistol is one the manufacturer doesn't have to "back up". It simply works as designed and doesn't require service beyond spring replacements. As a lot of the employees switch between the builders (Wilson and Nighthawk, specifically), there becomes even less of a difference between some of these builders.
Personally, I've owned a Bear, Wilson, and EB - and all have shot above expectations. 1911's of this grade will all out-shoot me, so any difference in accuracy is negligible. The difference comes down to fit/finish, what model fits your needs, and nuances such as trigger break, slotted or checkered grips, price, and whether the rep that answers your phone is having a particularly bad day. Here's a couple of notes on the the 3 above brands, off the cuff:
Baer - extremely tight, to the point of bing difficult to rack on an initial attempt. The mainspring housing is slotted, which requires some may consider an unnecessary cost savings in a pistol of this price point. Bear isn't big on frills, and delivers his pistols is a plain cardboard box and coated in CLP. My pistol ate everything I fed it, and accuracy is what you'd expect.
Wilson - their compact models and finicky on ammo, and Wilson will admit as much if you call and ask them. I have had zero malfunctions in ammo they recommend. Their trigger is the best of the bunch, and has no noticeable creep. Wilson has the habit of sending you the pistol with everything but a personalized letter from the builder, and they are largely an assembly house. If anyone else knows of their present machining capabilities, please advise.
Brown - he CNC's everything but the trigger, grips, and sights. Personally, I have respect for someone willing to invest in the capital and the technical acumen it takes to run a machining center, and can control everything except raw material within his 4 walls. Fit and finish is what you'd expect from a shop that machines their own pistols, and they seem to be the only builder that markets their pistols with the ability to "spec out" a lot of the builds. This could boil down to perception on my part, as they used to offer a build-your-own pistol, that the customer could spec from the ground up. They now offer a more limited range of models, but their build sheets still leave room for customization. Ed has managed to piss of a lot of people on the internet, and I recall some jack-wagon blathering into a microphone shortly after SHOT 2013 about him being rude. All I can say is I called his shop back around 2002, and he answered the phone. I had a number of questions prepared, which he answered succinctly, and said he'd allow a tour of his facility as I planned to be in the area (I never made it).
One caveat: I haven't done serious research on these guys in about 10yrs so if someone comes in saying, "Dude, they stopped doing that shit 10yrs ago", just assume I'm wrong.