I've stayed 14th floor concierge 3 times. I believe the single rooms can be made part of a suite if someone wants a 2 bedroom instead of a 1 bedroom. We've always had 2 queen beds. The regular rooms on the 14th floor are the same size as the rest of the tower but the because the bathrooms are larger and the balconies are larger then the lower floors, the sleeping area is slightly smaller. Because the sleeping area is smaller there is no daybed. One of the nicest things about the 14th floor is there is a concierge lounge that has 2 balconies overlooking the MK. So even if you get a Bay Lake view you can still use the balcony in the concierge lounge to castle watch. In fact, we request the Bay Lake view so we can watch the Electric Water Parade from our balcony and then we go over to the lounge balcony to watch the fireworks. Some other benefits of the 14th floor are check-in and check-out on the 14th floor without having to wait with everyone else in the lobby; a concierge staff member who handles only the 14th floor guests; a refrigerator in your room stocked daily with soda, water, and juice; and nightly turn down service without having to request it.
I've never stayed on the 12th floor but I have heard that refrigerators are not standard. You can get one but you have to request it. Also, there is no lounge but they set up the food and have a concierge staff member stationed right outside the elevators. Food service doesn't last as long as it does on the 14th floor. One big disadvantage to the 14th floor over the 12th floor is the hefty jump in price. Hope that info helps you out.