I stopped buying Behr a decade ago when the Federal Government forced the paint companies to change how they make their paint to save the planet from global warming. After that, Behr just wasn't what it used to be. Every now and then I'll have a client insist that I use Behr, and I'm reminded why I don't like it. My biggest issue is getting it to cover evenly, and for the wall to be all the same shade with just one coat. If it worked with 2 coats, I might not hate it so much, but I've had to do 5 coats for some collars. The darker the color the harder it is to get it right.
Glidden has always been a contractor grade paint. Same as Walmart paint. You can get it cheap in bulk, it looks ok from a distance, and when it's new, but it usually needs to be painted over again in a few years.
Valspar is my favorite for ease of use, and price. I can get better paint at Sherwin Williams of Kelly Moore, but for the same money, neither of those stores comes close to what Valspar does.
You can also get Valspar at ACE hardware.
Since Covid, when Sherwin Williams went crazy, I've been doing a lot more business with Kelly Moore. I rarely buy from Sherwin Williams if I don't have to. Clients decide this sometimes.
Cheap paint means you get to paint more often and spend more time doing it.