I've run Castrol in everything I have owner for probably 15 years now. My Expy and the wife's Explorer only get the Castrol Synthetic with Motorcraft filters. In fact, the Motorcraft filter is the only one I have run on all my Fords going back to my 90 Mustang. Castrol has always run like a champ for me and it typically is a little less money in these parts. Not that I would switch if it costs more though. It's treated me right all these years and I'll continue to buy it.
I've been using Mobil1 synthetic extended performance for many many years and have had wonderful service from it. Not trying to start a fight here as MC is a great oil. But two MC changes to one Mobil1 change pretty equals the same amount of money, only twice the work.