We have been to Russia and Africa with Tauck, and this was or first river cruise ever, although we have been on ocean cruises. The other reviews are comprehensive, so I will mention other points.
I recommend room 323 which is next door to Authur's where I could pop in any time for cappuccino, tea, cookie/snack to take back to my room, or to sit to see both sides of the river since this was the aft end. Just quick and easy.
Interestingly, the motor coaches we used had a bathroom, and we could actually use them. We have been on tours where we were not allowed to use the bathroom on the coach. What?
Not enough time in Vienna. There should have been 3 full days and a guided tour of the Kunst Historical Museum one of the most important museums in the world; and Vienna one of the most beautiful cities. What architecture! This was our second visit to Vienna.
I hesitate to mention since it is a personal preference. The rooms need an adequate dressing table for My Lady with a mirror and lamp. Obviously a man designed the rooms, not a woman. LOL
They were generous in providing me with a laptop for the entire trip, although Wi-Fi was as slow as molasses.
I did note there is no Doctor on the ship.