Hi Shanti!
We have stayed in both and loved our stays in both!! I guess that it depends partly upon where you want to spend most of your vacation? Epcot/DHS or MK? With all the work going on at DHS and soon, Epcot, that may have a positive or negative impact on staying at BWI, depending upon your perspective.
Our experiences/opinions FWIW:
BC
BC is centrally located, with convenient walking distance to both Epcot and DHS. We loved the beach feel and the proximity to Epcot makes you feel like you are staying in World Showcase - especially from the rooms that are closest to the IG. Dining options are plentiful and good with four other Epcot resorts and World showcase all just steps away. Rooms are beautifully decorated and comfortable. Some standard view rooms also allow views of the high fireworks from Illuminations. Storm Along Bay is a very special pool.
The things that we didn't like about the BC and few and very minor, but here they are: hallways inside are very long, winding and convoluted; some rooms have small balconies; room size varies (some are relatively small, almost cramped) and not all rooms even have a daybed.
GF
I'll start by sharing that the MK resorts are personal favourites. Any resort with a view of Cinderella's castle is magical to me. Also, the monorail, though not perfect anymore, still feels like a quintessential part of a Disney stay for us. The GF, Poly and CR are our three favourite resorts by far. If I were choosing between the BWI and the GF, it would be no contest. The GF has larger rooms, all with reasonably good views and almost all with balconies. The buss top has more seats than any other resort bus stop. The boat ride to the Poly and the MK is my favourite mode of Disney transportation. period. LOVE IT! Dining at the GF is great. From V & A's to Gasparilla's, we enjoy the dining options here (and at the neighbouring resorts of the Poly and CR) as the best that WDW has to offer. I love the beautiful lobby with frequent live music, the flowers in the lobby, the gorgeous pools, the walkway to the Poly and the peaceful feeling that a stay here brings.
Things that I do not like about a stay at the GF: transportation to any theme park other than the MK is less convenient - especially to Epcot, monorail transportation can be especially problematic. Also, unless you are staying RPC, you have to go outside to access any restaurants/shops/transportation.
I know that you aren't interested in a split stay, but It is what I would do (and have done) with exactly these two resorts. So, you obviously have great taste in resorts! LOL!
It looks like you have stayed at the GF in the past (as well as in other Epcot area resorts), so I doubt that I have said anything that you don't already know. It is nice to hear others' perspectives, however, when making these difficult choices.
BTW: I'm so envious of your two upcoming Disney Cruises!!! We still haven't been on one, but it is on my bucket list! For some reason, the timing has never been quite right.
Enjoy!!!