I believe the HR Boston's renovation is more recent than the Cambridge one.
I only stayed there pre-COVID and it wasn't very exciting, definitely no views of which to speak fondly. It felt a bit like staying in a department store, if that makes sense.
Boston to me is a very difficult market as properties are rather expensive and most, including other chains, not very good. Hyatt's line-up doesn't give it much of an edge over competition in my book.
Most attractive hotels outside Hyatt in my book: newly renovated Langham in the Financial District, probably the Newbury with a great loaction, but relatively small rooms, the Charles in Cambridge is ok, probably the MO.