Traveled to Boston for a week vacation with 2 toddlers and my parents. Slept us all very comfortably. Pack-and-play was provided and we used 1 air mattress we brought along for our 3yr old.
Plenty of pillows and bedding. Beds were firm but comfortable. Everything was spotless. The appt appears to have been recently flipped, and I would say we were one of, if not the first, renters in the space. Everything in the appt was high end. Location was very convenient with available on-street free parking. Close to stores to pickup anything you need. Great park nearby for the kids (Boston has AMAZING kids parks all over the place). Being right on a major road, it was easy to get out and go and drive into Boston; surprisingly, the road noise was not noticable (very solid walls). We did not use the outside space in the back of the house, although it was provided and also looked like a great place to relax.
Host was great to communicate with, and they also live on the 3rd floor. Appts are all hardwood floors, so noise does travel between floors (this was an issue with our two toddlers and one of the renters while we were there). We ran into some issues with the inner security door to the upstairs appts, and twice had to have the owner come down to let us in, so it was good having them onsite. Only other slightly negative was the kitchen was very sparsely stocked w/ regular cooking / foodstuffs. Maybe this will improve over time as more people rent and use the kitchen.