I was also going to mention that in December, a pool shouldn't make or break your decision. We were at the YC this past December and my kids made it into the pool only one day. They swam for about an hour and we're from New England.
Based on staying 7 nights, would you consider doing a split stay? I know that can be disruptive to some people, but it really does give you the best of both worlds. I loved being just a 4 minute walk to the back entrance of Epcot and having MGM as a 10 minute boat ride. Then again, after many stays at the GF, that is still my favorite. With the GF, you feel like you're at a more secluded resort. The YC/BC has more of a hotel setup and with the Boardwalk right there, feels much more lively.
The themes of the resort, definitely give them character, but I can tell you that I've never once felt stuffy or held my nose up higher just because we were staying at the GF

. The theme is a victorian, but trust me, there are just as many of us in shorts and sneakers as anywhere else on property. It's not uncommon to see park patrons walking alongside wedding guests though. Just something that never really bothered us I guess.
Both resorts offer basically the same amenities, with the boat rentals, beach, theme pool (YC/BC wins this contest hands down), quiet pool, arcade, healthclub (the GF wins in this comparison though). A few minor differences are that nearly all the rooms at the GF have a full size balcony, with some having a standing room only and only a very few rooms without. Also the views. When the GF says garden, they mean garden. You won't even glimpse the parking lot or road.
After all my rambling, I'd still have to suggest splitting, but beyond that, based on the age of your family, I think a monorail resort would be your best choice for now.
Tammi