We (family of three) had an awesome stay at the Treehouse. It was clean and had everything we needed. I cooked every day and the kitchen was well equipped for our daily cooking. There is a french press for your coffee (and even coffee that come as a lifesaver, when you arrive at about 11p.m.) and full electrical stove and oven, a dishwasher and a fridge/freezer combination (I guess, there was a microwave as well, but as I do not use it, I do not remember).
The location of the Treehouse was awesome. Very quiet and close to parks (with awesome playgrounds even for a 9 year old) and shopping ( We are Germans and after several years in the US, I was in heaven when I entered the Columbia City Bakery. Best bread and pretzels and croissants ever!)
But- Seattle is hilly (to be honest, I didn't realized how steep those streets can be) and the Treehouse is a nice (steep) walk up the hill. We had a car (parking was not a problem) but you can easily get around with public transport (bus and light rail).
I would recommend the Columbia Treehouse to my friends and would gladly stay there again. Thank you Jay for your hospitality.