Given the scheduling uncertainties of the Amtrak Downeaster, I'm considering taking the bus from Portland to Boston. I know Concord Coach is the main line to use. But I've seen that Megabus also sells fares on this route, and I believe I've read that they're actually seats on Concord Coach.
Does anyone have familiarity with using the Megabus fares? Are they actually the same buses as Concord Coach? Are there any downsides to just buying a heavily discounted Megabus ticket?
I notice that Megabus doesn't release ticket availability for the Portland-Boston route until much later than for other Megabus routes. I'm not sure why this is but if they have some arrangement with Concord Coach it might be tied to that. Any insights?