My wife and I are both "over 50" and we like the elegance and more formal aspect of Cunard. In particular, we love the QM2. On our honeymoon in 1983 we went on a Holland Amercian ship and enjoyed that, but have been Cunard exclusively since then. Except for this last summer when friends wanted to go on a Norwegian Cruise Line ship for a Baltic Cruise. Overall, I enjoyed it, but it didn't come anywhere close to the QM2 with respect to what I look for in a cruise.
My wife and I don't dislike children, but we prefer there to be very few of them on the ship when we cruise. We took the QM2 transatlantic during the summer of 2009. I recall hearing a young teenager at a next table say "This ship has the worst teen club I've ever been to." For me, that was a ringing endorsement of the QM2.