TL;DR -- Amazing location and host. Small studio like apartment with limited natural light. Occasionally loud depending on the other rental unit inhabitants. Having a garage was awesome. Great for short stays but may be difficult for longer stays.
I enjoyed my 30-day stay at Casa Fremont. First and foremost, Fremont is a great neighborhood. It's very central to the rest of Seattle. It's very walkable--tons of bars, restaurants, cafes, etc., close by (Fremont Brewing is a block away!). The Burke-Gilman Trail (biking, running, walking) is literally a half block away. The Troll is a block away. The location is fantastic and my favorite aspect of the rental.
Bryan is a great host and took care of all of my questions and solved any problems that came up. Tho I never met him, he seems like a great guy.
The apartment itself is small, probably ~300sf, and feels like a studio despite there being two separate rooms (bedroom and kitchen). You enter the apartment into the bedroom from the Koi pond area, and then there are two steps that lead up to the kitchen which has roughly a 6' ceiling. The bathroom is just off the kitchen and also has a 6' ceiling.
The apartment is partially sub-grade so it doesn't get a lot of natural light. With the blinds open, my neighbors could look directly into the bedroom (sheer curtains would definitely improve this and provide more privacy). Same thing with the two small windows in the kitchen. It did feel a little bit like living in a fishbowl with the blinds open.
Noise in the apartment depended on the other airbnb renters (there are three separate rentals total in the building, one on the same level and one above). At times it was bad, but I got used to it.
I loved having access to a garage for my car.
Overall, I think a two week stay would have been ideal for me, but the longer I stayed in the apartment, the more I longed for more light, more space, and more privacy.