Whenever I went on my first unsuccessful adventure into third level education all the way down in London town, I took the Northfolk Line, along with my sister and mum because it was the cheapest way of getting all my gear there.
It was a long trip from Liverpool to London so the last thing we wanted was an awful boat trip to add to the hassle of the trip. Thankfully, we didn't! On entering the boat we were offered the chance purchase a berth, which is a small cabin for sleeping on the usually long trip (5 or so hours). These were actually surprisingly comfortable and the trip went by happily in dreamland so I didn't have a problem. On my mum and sisters travels on the way back however, they missed out on the purchase of a berth and were forced to sit on uncomfortable chairs the whole way back.
So I guess it all depends on the circumstance on your trip. There are a lot of facilities, but not enough to keep someone entertained over the whole trip and without a berth, it could become a very long and uncomfortable trip. read more