Often the question comes up, “There are so many brand out there, which ones should I stick to?” And the answer is really as simple as, “It for the most part does not matter. There are a plethora of companies that make carabiners, harnesses, shoes and rope, but what it really comes down to is which brand sell equipment that meets your needs.
For instance, Scarpa is a popular climbing shoe brand. You’ will see their shoes in any place that sells climbing equipment. They are comfortable, they’ are reliable and reputable. But that does not mean they work for everyone. I have had several climbing friends say Scarpa shoes never fit them right, which is a pretty common complaint. I wear La Sportiva brand shoes because those fit my feet the best.
For carabiners and often times a lot of other climbing equipment, Black Diamond is a popular choice. Mammut it also a fairly well known brand for harnesses as well as Petzl.
At the end of the day, do some research into exactly what you need. Look up reviews for what others have said, ask other climbers what brands they tend to lean towards and go to stores to see things in person. That way you can be confident in the purchase you finally make.