Presuming I liked both resorts equally and the rooms were priced equally, I would choose the Poly concierge over the limited concierge services offered on the 12th floor for the following reasons:
-Poly concierge lounge is a two story dedicated area for the concierge guests with awesome views of MK and the lagoon
-CR 12 th floor services are set up in the hallway near the bank of elevators with limited seating
-Poly concierge lounge may be used at any time with food/drink provided from 7a-10p (continental breakfast, midday snacks, afternoon appetizers and desserts/cordials in the evening as well as drinks offered all day)
-CR 12th floor services are offered from 7a-4p with only a continental breakfast and afternoon snack
-Poly concierge staff is "on-duty" from 7a-10p
-CR 12th floor concierge staff is "on duty" from 7a-4p
That being said, if I was getting a great deal for the CR 12th floor
I would consider it (but would probably try to get full service concierge on the 14th floor instead).
Good luck in your decision........