No one has addressed the kid angle I think. I'm in the market for a first tandem in part to ride with my sweetie, but also, and perhaps mainly, to ride with my 6yo son. He's been on a trail-a-bike for a couple of years and seems to enjoy it immensely, but its attached to my commuter bike and so isn't much fun when we decide to go for longer rides. So I justify the tandem because I'll ride it with him. Riding it with my sweetie stoking is just an added bonus. She has a single as well, so another thought in my mind is that she can ride that while the kid and I are on the tandem, and with a little luck we'll all be about equal.