I keep looking at them and I just can't justify the cost. We LOVE France... we covered everything the Seine cruise does by spending a week between Paris and Honfleur for 1/2 the cost. We covered the South of France cruise the same way by spending a week down there with our own car.
I would love to see the Christmas markets but we're thinking of just spending a week in Cologne/Brussels in December.
I just can't justify it for what you get. Maybe it's because we like to drive in Europe and have no issues doing our own thing.
If you're not comfortable driving or doing your own thing then they're probably a much better option.