I've done the NYC-Boston trip once. The Boston end was underwhelming to put it politely. Back Bay station was just nasty. Even the Wikipedia pictures comment

I've done the NYC-Boston trip once. The Boston end was underwhelming to put it politely. Back Bay station was just nasty. Even the Wikipedia pictures comment on the haze and air pollution at the platforms. Getting a Charlie card took a few tries across a few stations. Acela? Acela was fine but it's both expensive (presumably because of the demand) and a lot slower than it ought to be. That entire stretch of Metro North(?) tracks through Connecticut? There's no good reason the track is in such poor shape and no good reason to limit Acela to a snail's pace. OTOH Acela still seems to be pretty popular, so perhaps Amtrak can afford to let it rot for a bit. Hopefully not for too long.