Judy and Steve's place is centrally located, they're really good hosts and the apartment has most of what you need to have a great stay in Cambridge.
My wife and I and our two kids (3 years and 6 months) stayed for a month in the apartment. The place is centrally located, close to both Harvard university (and Harvard square) and Porter Square, with many conveniences, supermarkets, restaurants etc. nearby. I walked every day to Harvard Yard in 10-15 minutes.
Judy and Steve were really good hosts. They responded quickly to our inquiries before we arrived, which made planning for travelling with children easier. Once we arrived they were easy to reach and they checked in on us, helped us to plan and recommend things to do in Cambridge, Boston and New England, and even introduced us to American traditions like Halloween and Thanksgiving.
A major plus was generous access to washer and dryer, something that is invaluable when travelling with small children. The place was also very clean and tidy when we arrived (even though we showed up a bit early).
Like all places in Cambridge, it's not super cheap but compared to what else we looked at we think we really got value for our money, with a full kitchen/living room area, a full bathroom with shower/bathtub, and a large bedroom on the top floor with a desktop/work station.
All in all, we had a great stay!