First off, my stay at the Optimism House Apartment was a wonderful experience. Very clean & cozy!
Check-in is very smooth and simple. Alison will give you a door code, and after that it's as simple as pulling a wire to open a gate, and then putting in the code on the door... and then bam! you're in. Once you're in, you're greeted with a multiple guide books for touring DC, a guide book for the apartment itself, and also a bowl full of snacks and goodies.
Alison is a very communicative host and answers questions very quickly. She was attentive to our needs as guests, and also asked us what we were comfortable with in terms of verbally talking and meeting. The house includes everything you could possibly need, minus washer and dryer on site. There are multiple laundromats to pick from nearby though, if laundry is required.
The kitchen came with multiple table top appliances, cutting boards, knives, utensils, pots & pans. If you really felt like you, you could cook up a four course meal in this kitchen.
The space itself is very cozy, yet spacious. I never felt cramped or overwhelmed by the space. The bright colors and the art on the walls add a nice comfy touch.
I'd say the only real downside, at least to me, was that the metro stop was a decent walk away (25ish minute walk). The neighborhood of Petworth is beautiful though, so the few times I walked to and from the stop was enjoyable. We had a rented car for a majority of the trip, though, so this really wasn't a factor for us to think too hard about.
I would fully recommend staying in the Optimism House Apartment. Alison is great!