On our first Viking Cruise we had Viking make all our flight arrangements and this worked with out flaw, perfect, easy, zero problems. Yes I did check to see if I could get better connections, and cheaper fares on my own, I could not. Using Viking Air is the way to go.
As a yacht captain, I can see well past any ship board facade, and it is clear to me Viking is the clear stand out in European river cruises. This conclusion is after 3 cruises with Viking and the opportunity to view other river cruise operators close up (as in rafted up alongside). What makes Viking stand out? The largest fleet, this allows Viking to accommodate their passengers when things go wrong, such as low/high water, mechanical failures, by having enough long ships to substitute ships and not have to cancel the entire voyage. Viking has the newest ships and built to a very high standard. The interiors are well appointed in a modern tasteful fashion. The staterooms are very nice, and the heated bathroom floor is one of my favorite things.
The dining, I personally am pretty easy to please in this department. but I'll give a 1-5 rating, 5 being the best.