Dino.
I only use one change of synthetic, and that's in the late fall/winter time between October and April. This is when it's not pleasurable to change the oil (cold weather, ice, and snow), so I just throw some QSUD in there for 6-7 months, put in a long(er) distance P1 filter, and call it good.
Otherwise I change much more often during the spring and summer months, using dino oil because I like the smooth feel of fresh oil in the vehicle. My favorite oil is now Valvoline, hands down. Nothing runs better. I change at 3k. It'd be a waste for me to change synthetics at 3k!
Vote 1 for dino here.