I just spent an evening at this Red Door and would have to say that it is definitely the best in the area (over Tyson's and Reston) but...
Downside: It is super hard to get an appointment here on the fly. Although the spa looks huge, it only has three treatment rooms (I overheard an employee say this). Be prepared to pay for parking. They were literally running me out and shutting the lights after me. It was only 7 PM and they close right at 7 PM. The tip situation was weird. Give the tip directly to the employee to make sure that they get it.
Upside: YES they do offer you cranberry juice, dried bananas, pretzels, apples, Andes mints and sesame sticks. They have a fully stocked changing room so you could keep all your shampoos, Q tips, mouthwash, razors at home and come after work. Sarah was a good massage therapist but she sounded like she might be leaving soon. Evangelina was an above average nail tech.