i definitely have favorite brands, many of which are mentioned in this thread. But am I loyal to them? Not really. I will check out my preferred brands/stores first, but if they don't have what I'm looking for I will definitely branch out. I'm not going to pass up on something just bc my brand doesn't carry it, nor would I continue to shop my favorite brands if I was no longer happy with their quality/price/selection. Not sure if that's what you're asking though?
blouses/sweaters/cardigans: ann taylor, BR, loft work pants: limited, BR dresses: BR leggings: zella
more laziness than loyalty though - if I know something works, I'll stick with that v. dealing with PITA return processes. I am more open when it comes to jeans, outerwear, lounge wear, tanks, shoes, jewelry, etc.