Just returned from 3 nights in Portland and thoroughly enjoyed staying at Helen and Ethan's cottage. It is a small (think studio apartment), but incredibly comfortable and cozy space - thoughtfully appointed with everything that's needed for a visit, including a great backyard garden space that expands the usable space of the cottage and a great kitchen space.
Two observations: If you want to stay in central areas of Portland, this is likely not a good choice. Portland is a small city - the cottage is in a super-quiet and very nice residential area, but not easy walking distance. So be prepared for good long walks, an Uber/Lyft drive or have a car if your trip involves downtown sightseeing.
The cottage is great, as noted, but there is no AC - not frequently needed in Portland. However, during a very hot spell, which happens in summer time , it might be uncomfortable if your threshold for heat is low (like mine!). Our hosts provided an extra fan for us and it was fine, but this is worth noting if you have problems with heat.
All in all, another 5-star AirBnB experience!