Overall - we had a great time staying at Keith's place & would highly recommend/return! The two of us stayed for nearly two months while also using it to work-from-home.
Keith is an incredible host and extremely responsive to your needs. For example, when we arrived and found that the WiFi was quite slow in the bedroom, he purchased an extender and got it set up within a day. Keith keeps the apartment very well-stocked - we had enough toilet paper, paper towels, detergent, etc. for well beyond the two months we were there. There are also plenty of kitchen items (pots/pans/appliances) and cooking essentials (e.g., spices). There is a ton of closet/drawer space in the bedroom but would recommend bringing extra hangers if you are coming for a longer-term stay with multiple people.
In terms of the place itself, the location is phenomenal. It is a quick (~15min) walk to Fremont, which is a vibrant neighborhood, and about 15-20 mins (or a 5min drive) up the hill to middle of Queen Anne, with lots of groceries/restaurants/etc. The Burke-Gilman trail is fantastic for getting out for a run/bike ride and is about a 10 min walk away. We especially enjoyed the natural light in the living room, the overall spaciousness, comfortable bed, and easy street parking.
Some previous comments have mentioned the apartment cleanliness - we actually found everything to be very clean, but probably the combination of less natural light in the kitchen/bathroom/bedroom and the older aspects of the place (e.g., linoleum kitchen flooring) may have created this effect.
The only issue we had while staying there was loud construction that continued on & off on the house next door. It appears to be nearly finished but would recommend checking with Keith if you anticipate this being an issue. Seattle's noise permits allow them to work from 7am-5pm on weekdays so really only an issue if you are planning to use the space throughout the day (e.g., work-from-home).