My family of four sailed out of Basel in December, 2104 on the Viking Magni Rhine Getaway.
Positives: New beautiful ship with a sleek and comfortable design; extraordinarily well-designed staterooms that maximize space and efficiency (NOTE: see below note regarding room odor); wonderful captain and terrific tour guides.
Negatives: 1.Having taken a Uniworld Seine River cruise two years earlier, I can say that Viking service does not match Uniworld's. If you can afford the price difference, opt for a Uniworld cruise. This was seen most strikingly in the dining room when at times, there was five to ten minute wait to get a fork or a refill on coffee (this may seem minor to some but it's a little frustrating when it happens numerous times.)