Stephen's review is quite accurate: it's a great location, a very nice townhouse, parking is great to have, but it does not merit a top rating as it lacks certain amenities (see his review for details), and in our case was not set up as well as it should have been.
Our host forewarned us it might be a bit too tight for a family of four, but we decided that we'd take that risk based on the excellent location. In hindsight we'd make a different choice as it really was a bit too small for 4. Taking the couch bed in and out was not convenient (or feasible for us based on the dirt I'll describe in a minute) and so we had to live with tight space in the living area. This was mostly fine as we spent little time in the townhouse as we were out exploring Seattle's many attractions.
I mentioned the setup was lacking. Unfortunately, even though the host knew we were a family of 4 and needed to use the couch bed, it was extremely dirty under the cushions / on top of the pull out bed. With no vacuum to be found, this just ended up all over the floor and seemed to aggravate allergies for at least the first day. There was animal hair in the couch dirt, although the host does not have a pet or allow pets - prior guests might have been bringing pets despite this rule. We were also surprised that the liquid soap in the bathrooms was nearly empty on day one of our weeklong stay; no refills. The rooftop area was very disheveled and did not resemble the lead photo on the Airbnb ad - so this was a bit of a disappointment. There may have been a storm before we arrived that contributed to its state. I believe the host will take care of these things for the future, so this would still be a good option for up to two guests.