Hilton Back Bay would be my choice, by a mile. The Doubletree is near nothing; the Hilton is near everything. If you need a taxi, there's always a line of taxis at the Hilton or across the street at the Sheraton; you'd have to call for a taxi at the Doubletree.

I stayed at the Doubletree 2 months ago, and many of their rooms are on the ground floor. So, if you want to leave your curtains open, sidewalk pedestrians get to look in. And you might be lucky enough to have a street person sleeping in your window.