Boston is a lot cheaper airfare, but parking the car is PRICY $$$$ (if we had room in the driveway I'd offer you some; we're right on the subway). Navigating to Logan is also a bit complicated. I would say far better to fly out of Portland, Maine or Manchester, New Hampshire; the parking is cheap and easy, the drive is shorter and you can still get non-stop flights at decent prices (Southwest does the MHT-MCO route, while JetBlue and AirTran do the PWM-MCO, and those are just the non-stops).
Of course, if you're planning to do some Boston tourism, then BOS would make some sense. And the city would love to have more tourists and there's plenty to see and do here (I'd recommend the Duck Tour first, plus the Science Museum and the Aquarium, among many other attractions). When in Boston, I'd recommend not driving, since the streets are confusing even for those of us living here; it is far easier to get around using public transit and your feet.
But you'll save two hours minimum flying from PWM, and maybe an hour of the drive flying from MHT. Plus the parking and hotels are cheaper.
Thanks so much for the advice. I think we will be going to Boston because we'd really like to visit there. But I fully understand your recommendation for PWM. That was our first plan. We would most likely go to Portland the following year and fly from there.
And thanks for the suggestions for Boston. We do have the Museum and Aquarium on our list, but I will look into the Duck tour (I've never heard of it). And I definitely understand what you are saying about driving there. My cousin went to school there and kept her driving to a minimum. We were planning on staying at a hotel near the airport. I hope it's not too bad getting around to those places from there.