I'm a repeat customer of many companies, but I wouldn't consider myself loyal to any company. In outdoor pursuits, Beretta, Sage, Penn, Ambassadeur, Scientific Anglers, Dillon, Smith&Wesson, Eagle Claw, Mustad, Owner, Culprit, Poes Crankbaits, St Croix rods, and a few others have made very good products for me and I will consider them before others. They have earned my admiration.
But brand loyalty is a very fragile thing. I used Trilene fishing line for years and then tried Sufix. That was the end of my relationship with Trilene. Sufix is just a better line.
Then there are the companies I have learned through repeated bad experiences to avoid: Lee reloading equipment tops the list, Hornady reloading equipment, Remington .22LR cartridges, very few others.