Since Ngaire is waiting for more information from Avalon, I thought I'd share my thoughts based on our experience on their Artistry boat (not the one you're looking at).

On the Artistry, there are only 2 of the "larger" cabins/suites - I think about 250 sq ft. The "standard" cabins are all the same at around 160 sq ft. Quite a bit smaller than what we're used to on Regent. It was very well appointed with the only negative being small bathroom (with very small shower - no tub). I believe that all of these riverboats have 3 decks - avoid at all costs cabins on the lowest level since some of the time the windows would be underwater.

If I recall correctly, the internet charge onboard was like $2.50 a minute. However, you're docked very close to (or in) town everyday so most places have an Internet Cafe that you can use. Also, I believe that the tours are generally included on most of these cruises. However, with a few exceptions (like Bartislava (which used a bus) and Salzburg (which is about 2 hr bus ride from the dock), the ports are very small cities/towns where you could actually just explore on your own anyways.

Food was very good - but not quite as good as Regent.