It has been awhile since I bought paint. But around Thanksgiving we decided to repaint a hideous "French's mustard yellow" guest bath that the PO's had applied.
This was somewhat on a whim, and Lowe's was our choice of poison. Actually, they were okay. Guys seemed fairly knowledgeable, etc. Only real oddity I noticed was my wife had selected two colors, apparently from different paint manufacturers, and we were informed they had to use that specific manufacturer's paint to mix the colors. I critically questioned this, as I had never heard this before.
Long story short, we purchased both Olympic and Valspar branded paint to get the proper colors my wife wanted. We chose "equal lines" of each brand, or as close as we could reasonably tell.
The Valspar went up first and covered the hideous yellow in one coat. I was very pleased with the paint and ease in which it was applied. Silky smooth really.
Unfortunately the Olympic was not as easy. It took 2 coats and a few touch up's to get the Olympic applied properly. It seemed more watery than the Valspar.
The cost difference was only $3 or $4 per gallon. Going into the project, I just wanted the cheapest paint and would have preferred all Olympic. Afterwards, I would gladly pay the small premium for the Valspar. For us, time was more costly than the few dollars extra the Valspar cost.
Now that the job is over, everything looks great -- even w/ the cheaper paint. I can't comment on longevity as the paint is still fairly new.
Overall, I would buy Valspar again -- I was very pleased with it. If I could try one of the premium paints like SW, BM, etc for the same price I would give that a try too. It'd be hard to go with a lesser quality paint though after seeing how easy the Valspar went up.