I don't care about the brand of paint, stain, or primer, whichever is on sale or the cheapest. It seems that no matter what brand you use, you need two coats, so why overpay? If I need to touch up some paint, I buy the same brand as the original.
A few cents about primer. Primer prevents mold and rust and covers imperfections. I don't like to get paint pre-mixed with primer, in my opinion it creates more work long term, the paint flakes off after a few seasons (outdoor paint), primer needs time to dry. But I haven't used all paints with primer, so, my opinion might change. You absolutely need to prime walls if you have skim coated them or used joint compound on them to patch holes and such. If you don't prime, your walls will have "flashing" after you paint them - painters term to describe the thing.