Myself, although definitely not a painter by trade have always used the premium paints from PPG or similar. I also start the first coat of primer with that 1 mfg. and stay with their products all the way to the clear coat. Yes more expensive but, 30 years later I have had professional painters question the age of the paint.
My reason for doing so is many years back I mixed some products and had bad results. It was a painful experience to strip a show quality paint job back to bare metal and I swore I would never do so again. Normally I contact the area rep for whichever company I'm going with, tell them what I'm doing, and follow their recommendations with no deviation.
If it's something I don't plan on keeping, different story