To me, the big issue is convenience. The BC is within walking distance of the Boardwalk, MGM and, of course, Epcot. I always want to stay at the moderates to try them out (especially POR or POFQ), but then I start to think about having to take a bus everywhere. Inevitably, I am back to the deluxes. Of course, for $1400, you could probably take a taxi every day and still save a ton of dough.
The other big issue for me is the food. If you stay at the CBR, you have a food court and Old Port Royale to choose from. Every other restaurant requires a drive (either in your car or on a bus). If you want to try another resort restaurant, you definitely will need a car unless you have the time for multiple bus rides. However, if you stay at the BC you will have 6 restaurants at the Y&BC, plus you are within walking distance of 6 restaurants at the Boardwalk, 5 at the Swan and Dolphin and God knows how many at the World Showcase. So if variety of food is important, the deluxe is the way to go.
My goal is to stay at a moderate next time for the first few days, hit AK (since that always requires a bus anyway) and DTD, then transfer to a deluxe for the rest of my stay.
Hope this helps.