I agree with what everyone else above said, but I would just add a slightly different angle. One of the pros of BC is that, in my mind, you can effectively avoid the buses for 2.5 of the parks. As mentioned, you can walk to Epcot very easily and can also walk (or boat) to HS. If you are avid walkers or are used to exercising, then that walk to DHS is really not bad, but you can take a boat in any event. However, another hidden benefit of staying at BC (or BWV) is that, while you have to take a bus to MK in the morning id you are hitting RD, if you leave the park early and otherwise have PHs, then you can monorail back to Epcot in the early evening and walk through Epcot back to your hotel. My wife and I do this on our trips with our young children. Getting on a bus can be really hard late at night. The ease of either walking/boating to a resort or taking the monorail can't be oversold. You can take your stroller right on and your kids can sleep through the whole monorail/walk/boat. Packing up the stroller to get on a bus, especially at night, is one of my least favorite things about using Disney transportation.
Of course, we basically start at the parks at rope drop and push the kids until they are done (around 7 or so). If we wanted to go back to the room in the middle of the day, we might think differently. And, if we stayed to close at MK, we might run the risk of not being able to walk through Epcot on the way home, nixing the Monorail option. But our kids are young, so we don't tend to close the parks other than Illuminations since it is so close to the resort.
One of the nice things about BC is that you can also leisurely walk (and partake in drinks) on the boardwalk or around WS in Epcot at night while your kids sleep in a stroller. We really like that. It gives us some adult time without being confined to a room. Not sure whether you can necessarily do that at BLT.