My partner and I stayed here for a whole month this past summer, and it was a big part of why we loved our time in Seattle so much. The apartment itself, neighborhood, and the host Tri-- all stellar. All in all, Naoko & Henry's apartment is the best choice to spend a short to longer amount of time in the emerald city.
The place itself is comfortable for two people and has everything you need to do work, and be productive if you need to be (my partner and I worked our 9-5 from the apartment for weeks!) -- can vouch it's great from a space (two desk working spaces), internet (fast, never had any issues), and amenities perspective (fully functioning kitchen to cook lunch/make coffee, etc)
The very central location of the apartment made it so easy to explore all the cool neighborhoods of Seattle by foot-- First Hill, all of Capitol Hill; all the foods, bars, restaurants, nightlife you could want, available via stroll or longer walk. Across the street and also mere blocks away is Seattle University campus -- a sports field and a serene park, easily accessible (walked through these many times in our stay here).
Finally, Tri is one of the best hosts you'll ever encounter-- so friendly and welcoming, helpful and providing of where to go, eat, drink, see, do; if you're in need of a recommendation or second opinion. I contacted him about an issue and he not only responded immediately but thoughtfully went above my expectations to help solve it.
One thing to note is you'll be able to hear (given it's closeness to lots of exciting, fun spots, in such a lively neighborhood) sometimes, on weekends particularly, some noise from the nearby restaurant when it's open late. If you need total, obliterating, deafening silence at all times, this may not be the place for you. If you understand that some muffled & light sound may creep in on a couple nights, you'll be fine.
My partner and I would stay here again in a heartbeat when in Seattle, and that should tell you everything you need to know.