I served this to some friends last night accompanied by the Citrus Salad with Olives and Radicchio and the Cardamom Butter Carrots (thanks, ymatsuda!) It really was fantastic and I received many compliments.
I recommend using port as specified, but buy the cheapest bottle you can find (I found a bottle of Taylor Tawny for about $5).
I prepared the dish the day before, which was very convenient, and, in step 5, I baked the pork for two hours because after 1 & 1/2 hours it still didn't seem very tender. As a result, the next day when it came time to warm it up for serving, the pork was super tender, the prunes were only just holding together, and the sauce needed no reduction. In other words: perfection!
I will definitely be making this again!