I am not 100% loyal but my make up bag is mainly Bobbi Brown . I swapped to this when Clinique discontinued the palest foundation shades. I like a natural no-make - up look.
I guess some of the time it's laziness as you get to know your way around a brand. (I only ever buy when there is 20% discount.)
Budget brand- don't really have one but Revlon and L'Oreal might be up nr the top.