If you are already at Hollywood Studios, seems to make sense to go with Brown Derby. I tend to pick things that involve the least amount of transportation hassle. We ate at Cali Grill in November and weren't that impressed.
I think @sullyfam gives good advice on the transport side. I still haven't eaten dinner at CG but have much enjoyed the brunch; will redeem that oversight this forthcoming trip. As for HBD, as long as it's not a holiday meal with the attendant mob of prospective guests who unwittingly spoil the ambiance and service with the implicit plan of management, I'm more than game to eat there. Bring on the beef carpaccio, Cobb salad or corn chowder soup and I'm in a form of heaven!