This was a great place to stay, and a phenomenal value. As other reviews have mentioned, it's a basement unit, and the bed is indeed very soft and a bit hammocky, but it's hard to find much else to complain about. It is clean and well stocked, has convenient and well-functioning kitchen appliances (there is a microwave now, by the way), and the wi-fi works great. Check-in was painless after the initial quirk of needing to send ID (which appears to be a policy of the building owner, not the host).
By far the best property of the place, though, is the location. It's in a gorgeous row of brownstone buildings in Back Bay, just across the Harvard Bridge from Cambridge and about two minutes' walk to the Green Line. If you're not from Boston and aren't sure how good those things are, let me assure you that those are very good things indeed. It's also essentially on Boston University's campus, which ensures access to lots of affordable tasty food within walking distance.
One last tip: the washers and dryers right next to the apartment door cost $3.00 per load, and only accept quarters. So if you're planning on doing laundry, you'd be wise to stock up on quarters before you arrive.