Well, I'm a die hard Maggie fan. I auditioned a lot of dynamic speakers, including Dali, Dynaudio, Magico, Sonus Faber, Aerial, and Theil, ranging in price from 7K to 17K. I ended up buying Magnepan 3.7's. It was an easy decision. The only speaker I liked as much as the Maggie was the Sophia at 17K. BUT--- I would not go in that direction if I really wanted to stick with the BAT-VK55's. You will however find people who swear by tubes with Maggies. Most planars tend to be rather inefficient, and they tend to like plenty of current. To me, that argues strongly for solid state.
I already had my system built around Maggies, since I was replacing 1.6 QR's. It just made sense to spend 6K on the 3.7's vs 16K at a minimum, and then not really knowing if the rest of my stuff would mate well with the Wilsons. If I were you and I already had the BAT's, I'd try to find a used pair of Sophias. Those are mighty fine speakers, they are very flexible with respect to room placement, and they are not that hard to drive. The BAT monos are outstanding amps. I could see the BAT's and Sophias being a pretty sweet combo. I have not heard the Watt-Puppy 5's, but it seems there is a consensus that Wilson has come a long way with the new Sophias and Sashas over older designs.