My recommendation would to be to familiarize yourself with these different neighborhoods, and then prioritize your needs for a home. I am fairly certain that you would be able to find a great home in all of these neighborhoods, so it makes life easier when you are comfortable with where you are going to be.
I have included a link to a website that might be helpful. If I can be of further assistance, please don't hesitate to contact me.
I hope this information was helpful!
Hillary Nash McAuley
Nash Holdings Co.
Exit Elite Realty
All those areas offer a lot, it depends on what you are looking for. The Ritz has the LA Sports Club, two restaurants, the hotel in the building, as well as the Foggy Bottom metro a short walk away. It is a busy area with lots going on. As agents we cannot talk about demographics, it is against our code of ethics. I would recommend visiting the building/neighborhood at different times of day so you can get an idea of the area.
Rosslyn has two newer high-end buildings, the Turnberry and Waterview, as well as newly constructed Gaslight Square which is between Rosslyn and Court House.
Please let me know if I can be of further assistance, I would be happy to go into more details about different buildings/properties in these various areas with you.
Please contact me so that I know exactly what you're looking for your new place so that I can server you better.