MC Syn Blend in 5w20. Less expensive than PYB in that weight, $11.50 v $12.50. That plus, starting with the switch over to 5w20 in 01 MC SY BL was the most readily available 5w20 at Wally in value priced jugs. Been using it since, when others not on sale.
In other weights PYB, because it's less expensive and comes in jugs, MC doesn't.
Price doesn't matter? Flip a coin, can't go wrong with either for an average 5K OCI.