Ford vs Holden. Mercedes Vs. BMW. Toyota vs. Nissan. Nike Vs. ASICS. Apple vs Samsung. Nikon vs Canon.
I studied Consumer Behaviour at University what seems like a lifetime ago, because I wanted to find out why people had a preference to to particular brands when the product offering was relatively similar. It may be because of a good experience they have when they buy such a product, so they keep buying it. It may be a social expectation. Perhaps they had a terrible experience with Brand A and switched to the competing brand. Perhaps a brand has a particular status or positive culture that the person wishes to identify with. Either way, all of the brands listed above are respected, but pretty similar.
Case in point; cameras. As you may have gathered, I love cameras and have had one since I was a kid, much like my son Ronan, pictured above. I've had many brands, but I have a soft spot for Nikon. It is completely irrational. I'm not a Pro photographer, so it doesn't mean the difference between eating or not eating. It's just a feeling that I got as a kid, drooling over Olympus and Nikon cameras, specifically the Olympus OM and Nikon F models of the 1970's and 1980's. I vowed that I would always have one or the other. I had an Olympus in the 1980s. Unfortunately, Olympus seem to have lost their way when Digital SLRs became affordable, and I bought a Nikon DSLR a few years ago, and have continued to buy Nikon since. For me, nostalgia seems to be a strong buying motivator.
Marketing hint: If you can sell a person something that is attached to status, a cool subculture, or a particularly pleasant memory of days gone by when things were made to a standard and not to a price, you have a strong point of difference to your competitors.