I highly recommend staying at Martha and Tim's place. They are great hosts, and they truly thought of everything a guest could need (including homemade muffins!). They made useful recommendations for my stay and have a variety of books that can help someone new to Portland explore the area. They are also very nice people and I enjoyed chatting with them about how much they love the city.
The space is very clean and airy, with a nice balcony- perfect for hanging out and reading. If I wanted to stay in, there was a fully stocked kitchen for cooking and an area to watch TV/a movie. This made for a very comfortable experience overall.
The location was just what I needed- a quieter neighborhood but still in walking distance of different kinds of restaurants and bars.
I will definitely be re-booking when I come back to Portland! :)