I visit Boston all of the time for work and have stayed at over a dozen hotels there throughout the years. Unfortunately the Hyatt choices aren't great, the Hyatt Regency downtown is your best bet. The location is pretty good, breakfast is ok, so are the rooms. Parking is free on award stays.

If your open to other hotels, my favorites aside from the obvious (Mandarin Oriental, Ritz-Carlton, Four Seasons) are the Boston Harbor Hotel and The Newbury. The InterContinental is also pretty nice as well for points stays.