Are you talking about a 7 or ten day cruise ? For a seven day all the lines are good. I am talking Princes, HAL, NCL, Celeb etc. For a 10 day which will cover Quebec and/or Montreal I would say Princess, HAL or Celebrity pretty much in that order. The seven day trips are pretty much in a port each day so you will be out of sight of land for a short while. Certainly the sea can be bumpy at times. On our three C/NE cruises (one 7 day Princess and two ten days Princess and Celebrity) we experienced very little rough weather. I think the bumpiest it got was exiting the Gulf of St Laurence and entering the Atlantic and that was quite mild. Canada/ New England is a beautiful trip. We are currently booked on the Crown Princess New York to Quebec City. The above is only our opinion and other cruisers may have a different view. Happy cruising and smooth seas !