I stayed in this apartment for two nights with my family of 4 (two children under 3). It was incredibly convenient to have on-site parking, elevators, and a full second bedroom and bathroom while being a block away from the Metro. The area is great with a nice park/playground and several coffee shops, restaurants, and bars in walking distance. Highly recommend for anyone visiting D.C. and/or Arlington.
As others have noted, check-in was a little cumbersome only because you have to get key fobs & an assigned parking space from the front desk, only after parking either in the garage or elsewhere. I figured it out easily though and the Sojourn team was very proactive in offering help, should I needed to have asked them. No regrets!