I'm not a fan of compartments. I like to look out of the window when I travel by train and I find it a lot harder to see out in a compartment than in an open carriage. Then you've got other people to deal with. If you're in an open coach and someone else is sitting on the other side of the aisle then it seems less hemmed in than if you're sharing a compartment with that same person, even though you've got exactly the same number of neighbours. In an open coach people can see if other people have got off and so seats are free; that's not as easy in a compartment coach - and if it's not a corridor train then there isn't even anywhere to go: it's quite possible for one compartment to be empty and the next to be absolutely heaving.