Just got back from the CR two weeks ago. The CR in a Tower room with a MK view is something I would hope that everyone could do at least once in their lives. Cinderella's Castle, Wishes, or Holiday Wishes every night from the balcony of your room is pretty special if you're going there mainly to visit MK.
OTOH, IMHO, the Poly is also awesome with super theming, and I would choose Poly over CR if I couldn't get a MK view room.
I believe you mentioned that the MK is where you'll be spending most of your time, so my vote(money aside) is for CR with a MK view room. If you do book at CR in the tower, ask for as high a room as possible-we were on the 7th floor in November and had no real issues with noise, but I would think the higher the better.
One other thing about CR that I noticed in the tower-When everyone was asleep and it was very quiet in the room, I could just barely feel(hear?) when the monorail came through the atrium-not annoying at all-very cool and I'd fall asleep knowing I was at WDW and not in my own bed. Anyone else notice that?