We take a River Cruise every other year and have done Viking, AMA, Uniworld, and Tauck--- and Tauck is, by far, the absolute BEST.
It is ALL INCLUSIVE - so everything is included - even top shelf alcohol, beer, wine, cocktails any time you want, 24/7.
The service and tours and excursions are also top notch.
We have done them all twice and Tauck 5 times.
You don't see them advertise, as they don't need to and they don't hassle you with mailings, catalogs like others do. They are a family owned business for over 80years.
We have found that by the time we tipped, paid port charges, had a few drinks (which aren't included on the others except Uniworld), that the cost of Tauck isn't any more expensive than AMA and Viking. Plus, all excursions are included and the guides they use are much better than the other lines we have been on.
You tour with a small group in the morning to see Cathedrals, learn the town/history, etc, then around lunch time, they release you and the rest of the day is yours. They run shuttles back to the boat every 30 min, so you can go back when you are ready.
Their breakfast buffet is the best I have ever seen.
Tauck is just super special - gifts everynight on your bed from the area you visited that day, special food treats on the bus as you travel to the town (the regional specialty), the meals on the boat are 5 star with a very regional menu of where you were that day, plus, you can always get steak, chicken, vegetarian, pasta, etc - and they pour endless glasses of regional wine at dinner. They also have another restaurant onboard with 'less fancy' food like fresh pastas, salads, burgers, soups - all amazing.
We love their Vienna to Nuremberg cruise, but you can do longer ones too.