Work Out Fitness Clothing

I have created and i am testing various pieces of clothing for fitness, I've been testing for over a year and i've found a good tshirt, good summer hoodie and i'm looking into another slightly more expensive winter hoodie. shorts are way to expensive to buy blanks.

Question is: When you buy fitness branded clothing, what do you look for other than the brand itself. why do you buy gymshark etc. what would you like that you can't find? I've found the perfect tshirt i think for running gym etc. but let me know.