Excellent, well-organized craft beer selection, nice staff, and relatively fair prices. Atlas has a fairly unique setup, with it's connection to Row House Cinema, and its tasting room downstairs. They also eschew large coolers of beer in favor of individual bottle chillers that work well for grab-and-go. The only downside of that approach is that the chillers take a few minutes to get your beer to drinking temps (for those of us who prefer cold beer), but the staff is nice and a brief conversation about beer or whatever will pass the time quickly.
Overall, Atlas is great for the craft beer curious, and it's a great alternative to the case-focused distributors in the area.