That there's very little, if any difference. Especially in apparel.
Shoes are person specific. So many people just think "These Nikes are uncomfortable, all Nikes suck." Nevermind that those Nikes weren't built for their feet, or in a lot of instances, what they are even using them for. There are several different pair of Adidas cleats that get fantastic reviews, the famed Nike Vapors are only marginally better and don't fit a number of players properly. UA did make extremely crappy footwear when they first came out, but they've reengineered the whole process and are equals in the department as well.
I am currently running around 20-25 miles per week. I have four different shoes that I run in. A pair of Brooks PureCadences IVs, Newton Motion IIIs, a pair of Mizuno Sayanora IIs and an older pair of the PureCadences that I use to run on the beach. I could buy a different model of any of those brands and they fit me like crap. To further explain how specific models are made for specific feet, I was using this fancy lacing system for the Mizunos and hated them. Switched back to regular laces and now the Mizunos are my favorite pair for speed work.
What it basically boils down to is what you like and what you feel comfortable with. I don't like the way UA cuts their apparel. Their wicking fabrics though work just as well as Nike or Adidas.