I'm a broke college student and I've done Montreal-Manchester by bus a couple times. It's on the same Montreal-Boston route as Montreal-Burlington, although it's a lot longer, obviously. I guess it depends on what kind of comfort you're used to, but I quite enjoyed the ride. The bus usually isn't full, the scenery is nice, you have a bathroom available at all times (massive plus for someone with bladder issues, let me tell you!), the seats are comfortable and it's just a generally nice time to chill/zone out. People mind their own business, and they're mostly broke kids like myself. The border crossing is run seamlessly, though I've seen a couple people get turned away when trying to enter the US - not fun to witness, but in most cases it was their own fault. Obviously not everyone will be patient enough to enjoy the ride, but I quite like it, especially for the price!