I prefer new, but not without a deal. Historically I've bought severely aged new inventory, leftover model year, unpopular configuration kind of stuff that sits around on dealer lots until they just want it gone. $10k off MSRP kind of stuff on a mid-priced truck. That really, really helps knock down that first year depreciation. It also requires being somewhat flexible on colors and options. I wouldn't buy a 4 cylinder if I was looking for an 8 cylinder, but if I got blue paint instead of black, or a great deal was lacking a minor option, I'm willing to overlook those things for savings.
Used <> used. Condition and history are everything. If I'm buying used I'm looking for cream of the crop. The truck from the guy who religiously pampers it, and then decides a year later he wants newer and nicer. NOT the ex-rental vehicle, or the crew cab traded in by the family with 7 kids who like to throw food, and the oil only got changed when there was time long after the oil life monitor started alerting.