I don't have any idea how natural the MCA midwives are, but they are there, and birth in a hospital, which seems to be what was wanted. Do you want natural as in supporting a drug free birth? Because I think that's what you'd get with them, especially with a prior vag. delivery.
I used BirthCare in Alexandria for my first, and loved them, but we need to be in a hospital with a good NICU this time around, and Shady Grove is the only close hospital with jacuzzi tubs, so MCA it is! They are slightly more on the medical side of things - for example, I am constantly peeing in a cup, where I did that once for BC - but they are not nearly as invasive as the OB I started this pregnancy out with. Other than that, the appointments are in and out, answering all my questions, and reassuring me that they will let me do what I want to do during the birth. Yeah, there's a chance you'll get 1 of 5 on-call midwives, but that's the same with any practice delivering at a hospital.
The practice at GW sounds fantastic, but it also sounds like a nightmare getting to the appointments and dealing with rush hour and parking. I just don't like dealing with driving in that part of town, though metro is an option.