So, a bit of testing of this build and I am a fan.
The Set-Up for this deck is alot faster than I expected, but Spiritomb was the definite icing on the cake. While I am still somewhat peeved at the slow energy attachment, over a bit of testing against some players I found that the entire deck relied on the proper attachments. Early games tend to favour Dusknoir while later games let you shift to Flygon.
The only modification I found was that Memory Berry proved to be completely useless to me, rather, since I had enough beatdown power once I got the hang of it and I never drew into it when I needed it in my games, so my suggestion is to replace it with another Luxury Ball to provide an easier top-draw (1/30) in case the Spiritomb tactic goes to the dogs.
If I cannot find a more fun to play deck than this one, my friend, rest assured I will be playing this for Cities.