Actually I have not sailed on any of them. I am just starting to focus on the River Cruises.
I went to Budapest for three days and saw as many ships as I could in that time. AMA, Avalon Scenic and Tauck I chose as the top four based on the inspections of the ship, size and layout of the cabins, one meal on board each ship, the features and inclusions on the ships, and value for dollars.
AMA and Avalon came out about even when I read hours of reviews. I also had clients that had researched themselves that wanted to try AMA as they felt this was the line they would prefer. In fact the client that asked me to do river cruises that got me into this area in the first place wanted to try AMA. I also found the one meal I had on AMA to be outstanding, that is why I show a picture of it on my report. So the first group cruise that I could do was the Christmas Cruise in December 09 and for those reasons I chose AMA
I am certainly just as interested in Avalon, Scenic and Tauck. Eventually I will get to experience all the lines. Just got such a busy schedule I cant fit it all in just yet. If you look at my website I show AMA, Avalon, Scenic and Tauck as the lines that I will focus on representing.
http://www.bkrivercruises.com/ It is difficult to determine the best line until I have had the opportunity to sail on all four and have first hand experience. It all just takes time. If any of the lines, including AMA do not meet my expectations then I will not represent those lines as my recommended choices.
I think AMA and Avalon are very close, Scenic I really adored the cabins with a real balcony and the style of the ship, this line is more expensive. Tauck is much more expensive and in a different category.
This does not mean there are not other good choices out there but I had to make a decision based on what I felt the majority of people would find the most appealing. I always prefer to focus on a few lines and strive to understand that product well.