My wife and I came to Boston for our 10 year anniversary and had never been before. The host, Steven, was very accommodating and provided very clear instructions as well as recommendations for the area. The rental itself is in a great location as it is a 5 minute walk to the Train, 10 minutes to North End and all those amazing Italian restaurants, plus there are lots of bars and other restaurants in the area.
Check-in was very easy but the building is old with a winding staircase. There is a very small elevator though so depending on how many bags you have, you might need to make a couple trips. Access to the unit was simple and everything was very clean. The bed was also large and comfortable so that was a plus. Some negatives though, the air (cool or heat) didn't work at all, I had to cast TV from my phone, and the hot water lasts for 1 shower, so hopefully you are first.
Overall it was a good experience for our short time in Boston.