BOZZ, we recently stayed at the Hotel Commonwealth in Boston, on Comonwealth Avenue - it too is in the Back Bay area. We chose it as it is not yet another square box of a hotel, AND we scored a marvellous deal with booking.com for a 3 night stay in their Commonwealth (junior suite) rooms. Thoroughly recommend this hotel: it comes up as #1 on TripAdvisor, and it thoroughly deserves its ranking. Great restaurants and eateries just nearby. It is also quiet.
Thanks JetLagged, I've seen that Hotel Commonwealth rates highly. And it's good to hear that those Trip Adviser reviews are justified. I've made refundable booking, so will still be looking for the better deal.