if your talking about something like Viking.. its lovely but they don't allow children (your son) on those trips and they are catered for 65+.
My honey and I went on one this year, Budapest through Netherlands. There was one large family there that brought their 20 somethings along and then there were us, mid 40s, 1 other couple mid 50s, and then most were able bodied 70+.
I personally enjoyed it because you got off right in town and most travel was done overnight while I was sleeping comfortably in my bed. Food was decent, wine was plentiful and free at breakfast, lunch, dinner .. It was catered for education mostly, lots of historical guides walking you around which is what we wanted as its one thing to study architecture in school, another to be in the middle of Vienna with all those gorgeous buildings to do comparisons on. We adventured out often after meals and got to see a lot .. leaving tourist spots to the morning guided tour.
Most younger people would probably be bored after awhile as you can only see so many churches. I know most go via the bus/train tours, but I think you have to be young enough to enjoy that too... long stays on the bus/train, traveling most of the day, to drop into a random hotel, checkin/checkout, slog to the next town with sometimes only a few hours in any given town...that wasn't for us either. Next trip we do will likely be a bike tour to really get time to see stuff and wonder with our hotels planned so we dont' have to worry.
Whatever you choose, like all these tours, really check the amount of time you will be in each town and when.. ie if it ends up in Cologne and its 6PM and you wanted to see the great Art museum they have there... well its not going to happen. That's what made us decide on Viking, though ironically we ended up on Cologne on a Tuesday where all museums are closed. (so much for my planning).