The Beach Club would give you much more space and easy entry to Epcot during F&W. The pool is great, but if you don't go in with your GD, you won't be able to see her at all times (it's large, spread out, etc., so fun for strong swimmers, but not great if you want to relax on a chair and watch her). Also I believe that the suite would give you access to the club level lounge with its snacks and drinks.
The GF is lovely, and it would give you easy access to the MK. There are 2 nice pools, both of which make it easy to keep your eyes on a child if you need to.
It just depends on what you prefer... More space? Close to MK? Close to Epcot? Both are nice (we have stayed at both of them), so I don't think you can go wrong here.