I don't mind using Amtrak for business travel between Boston-NYC. Parts of the trip are pretty scenic. You can get delayed quite a bit by other rail traffic, but as you point out, you still have a table and can move around. Acela isn't much faster, but it is a lot smoother then the regional trains.

But for family travel, we end up driving, as the cost for 4 people is just too high (even considering expensive NYC parking).