Don't panic,, everyone's that is picking it up is losing it just as fast. As was said, this is not a official launch of the market, rather just a testing /ramping it up "stage. Each day they will be lighting up more and more towers to test in the Boston area . Hang in there.
I work in Back Bay (LTE isn't working there) and park my car a couple blocks away in the South End. LTE's working in the South End, but as soon as I cross over to go home in Dorchester, I'm back on 3G