I used to be inordinately fond of the Sally Viking Line crossing in the early 80's, the Smorgasbord buffet may have had something to do with that
an added bonus was, that with only a limited number of crossings per day, a cheap 60 hour ticket meant catching the last crossing on Friday night, but then not having to leave Luxembourg until a sensible time Monday morning ,rather than 0500 with P and O
more recently, I have found Norfolk lines to be a very civilised option, with generally fewer families and rather more HGV's with volatile loads (leads to more interesting conversations )