We really looked forward to our Avalon river cruise but, alas, we were disappointed in many ways. Probably the biggest drawback was the inadequate air conditioning in the cabins. Even with the curtains drawn and the lights off, our cabin on the second deck would be 27 degrees C. (about 80 degrees F.). The ship maintenance crew worked on the system a couple of times, then disappeared with no change in the cooling. Passengers on the top deck had it even worse with sun beating on the roof. The ship just can't cope with upper 80 degree weather.
Internet was available only when docked and even then it was spotty. (Avalon is already advertising free Internet access for 2012 but they happily charged us the full fee this year.)
The buffet breakfast and lunch offered a good and varied selection, but the dinner entrees were often skimpy. Standard chicken and salmon entrees were always available and often preferable to the offered entrees.
It is also unconscionable that the ship served "fresh" fruit cups containing canned fruit cocktail with a bit of fresh fruit dressing up the top. This was peak fruit season locally -- we bought some wonderful cherries port side in Hungary -- but the ship did not offer berries, cherries, and other local produce.
Then there was the coffee. The coffee in the dining room was seldom good and, later in the day, it tasted as if it were held over from the morning. The ship had a self-service coffee machine that, like many gas stations in the US, offered lattes, cappuccinos, and coffee, all virtually undrinkable. There was a real espresso machine in the bar -- for an extra charge!
The ship staff was friendly and helpful. The passengers were most enjoyable and there was friendly, informal mixing at meals. A positive for us Americans was that nationalities were tilted toward Australians and New Zealanders with Americans in a decided minority.