I've grown up in DC for most of my life, and there's a lot of basement apartment conversions in downtown townhouses. This is absolutely one of the best. Very modern furnishings and equipment, a Nest thermostat for perfect climate control, comfy bed, private outside space, coffee ready to rock for the morning, everything you need for a place that feels like home as soon as you walk in.
But that's not the best part. The best part is Sylvester, who is instantly available, wants you to have the best stay possible, has local (walking distance!) recommendations for outstanding restaurants, and most importantly: takes time to put personal touches everywhere in the space such has having the towels presented and folded crisply on the bed for your immediate use, chocolates sitting on the coffee table when you walk in, and specific effort put in to make everything feel like it was prepared just for you.
This apartment is at the top of my list for places to stay when I return to DC.