Nearly everything about our Viking experience was excellent - booking, meeting and transportation to/from airports, welcome on the ship, room accommodations, dining, shore excursions, Dominic our cruise director, super-friendly and helpful staff, and much more. Our first Viking cruise has probably ruined us from ever booking another cruise company.
The Grand European Tour was wonderful - the ports of call ranged from beautiful small villages to large interesting cities like Budapest, Vienna, Nürnberg and Köln.
Not perfect? Our captain had less than a sparkling personality, the free wifi disconnected too often, the ship-to-shore gangplanks were sometimes steep and wet, and passenger ages ranged 45-80, definitely a grey-haired crowd.
Not Viking's fault, but our American Airlines connections between Philly and Budapest were on vintage 1980s airplanes - great food but embarrassing video screens and no USB ports.
Viking is at the upper-end of cruising quality and price, and you definitely get what you pay for. Except for extra shore excursions, our cruise was nearly all-inclusive, including wine and drinks at lunch and dinner, and well worth it.
I can't recommend Viking enough - we're done with Holland, Carnival, etc.
Double-sized room was comfortable in every way - well worth the extra cost.