My first river cruise, but have traveled a lot with Tauck, so I had the Tauck high quality/service expectations going into it, and they were met. They have a quality crew partner in Scylla and to the casual observer they seemed to work well together.
I've only been on a few small-ship cruises, but felt that the cabin size and storage space were more than adequate (though I travel with only a 22" suitcase and a backpack). The shower was excellent--good water pressure and no sharp edges on which to bang elbows. Good ventilation, too; could wash out "smalls" in the morning and they'd be dry by the end of the day.
Tour was Tauck first class. Nice shore excursions most days, always with the option of staying on the ship, and often with the option to either return to the ship for lunch after a morning tour, stay in town for lunch and return at around 3, or even to head back into town for a quick visit after lunch. Very accommodating and flexible, with their own coaches (with bathrooms) and great drivers.