MP Inn was lovely. Reserving through an online discount B&B website for the price we paid (or what we were willing to pay) got Room 17 on the third floor. It had a small fridge, sink, desk, small closet, and a private bath with a removable shower head due to the slope of the ceiling. My husband and I found it QUITE FINE.
The breakfasts were excellent, with a choice of full or continental. We like walking and enjoyed the 10 minute walk to Harvard Square where we had business during our 3 day/2 night stay. We also rode the bus back one night (the 77 or the 92). The bus stop is less than a two minute walk from the Inn - - and don't worry, you don't hear traffic at all because the inn is on a quiet side street. (Cute shops nearby, btw.)
I much preferred this experience to any hotel in Harvard Square, but if you plan to spend oodles of time in your room, you may want a different room than the one we were in (for a higher price). We may end up doing that when we return. But if you essentially want a clean, comfortable place to stay with a sense of charm and a good breakfast to get you started for the day, you will not be disappointed.
