We stayed and Ella and Will's apartment while visiting Boston for my sister's graduation.
The apartment was big enough to accommodate three adults (one bedroom and one sofa bed).
Around the apartment there are cute little places to buy pastries for breakfast and it is very family oriented.
If you are planning on staying here to spend most of the time in the downtown or Commons area, beware of the distance. It is absolutely doable with Uber and taxis, but it's a little far (about 20 minutes in regular traffic, and between $15-20 per ride)
The apartment itself is beautiful, lots of light and has everything you need. We didn't get a chance to meet the hosts, but Ella was really forthcoming, accommodating and quick to answer emails. They took time to make sure our stay was going ok (even though they themselves were out of town).
I would highly recommend their place and would definitely stay there again.