When ever the word best comes up, the answer is always, "it depends"
I won't use a powder that won't meter well in a progressive press. I don't care how good it is. All my shooting is done in Southern California. Since the weather is the same all year, I can get away with a powder that might not be as temp stable as some others. I personally like AA2520. it meets my needs. It produces accurate loads with my rifles in bullets weights as light as 53 grains to as heavy as 180 grains. My .308 bolt gun and my 223 AR15 both get fed ammo thats loaded with the same powder. I load the 53 grain vmax, the 75 grain BTHP, the 175 grain Nosler CC and the 180 grain super shock tip all with the same powder. So I can shoot f-class, hunt deer, pigs, coyotes, ground rats, and who knows what else with ammo loaded with one powder. AA2520 is MY "best"