Motorcraft all the way.
I use the Copper ones, because they have a more consistent power output and don't surge much at all. But you don't have to go with the Copper ones as a daily. But definitely go with the Motorcraft ones ... by the way ... we have several members that work at Tommy Vaughn Ford off of Shepherd and i10 ... they possibly could help you out a bit on cost.
Give them a call, tell them you are Focus guy recommended from TeamFocalize ... should be good to go.