There are 6 of the octagonal king deluxe rooms - these offer panoramic views of the GF grounds, beach, monorail, and some have very limited views of the MK. They have a unique layout, are larger in size than a standard room but do not include balconies - just lots of windows.
There are also 9 king deluxe rooms in a private wing on the 2nd floor of the Main Building, situated just above Gasparilla Grill & Games. These are basically the same size as a standard GF rooms. They do have a jacuzzi bathtub, balconies, and a direct view of Cinderella Castle. While touringplans.com is not great for the accuracy of the room type they do show the locations well from the room finder tab. You can clearly see floor 2 that is only the king deluxe rooms and the corner locations of the 6 king octagon rooms on floors 3,4, and 5.
The type of room is by request only with no guarantees. I personally prefer the larger rooms located on the lobby atrium side. Those that want a balcony or a theme park view may prefer the rooms on the 2nd floor. If you received one of the 2nd floor rooms you would have a great view of the MK fireworks. I don't like the access to the 2nd floor rooms. You cannot really view fireworks well from any of the lounges or balconies. A better view if not available from your room would be from in front of Gasparilla's or on the boat dock.