This tour surpassed our expectations in many ways. We were provided with reliable, sturdy hybrid bicycles that were well maintained, comfortable to ride, and decked out with a headlight, tail light, a (rather challenging to open at times) cable combination bike lock, large waterproof handlebar bag (that allowed easy viewing of directions and maps), bike computer, waterproof pannier, and bike tools/flat repair kit (which we never needed). Who cares if they weren't Trek bikes? (They were better than my own Trek.)
On the evening of our arrival in Passau (day 1), we were met at our hotel by a tour representative (fluent English-speaking) who provided us with the bikes (which fit us well), maps and cue sheets as well as an overview of our planned tour and ideas for places/activities to check out on the way. Each hotel we stayed at appeared to have been thoughtfully chosen to provide us with the best local experience--the least "upscale" one was in Schlogen, Austria (the room was quite basic and we needed ear plugs), but we had a spectacular view. The most upscale was Schloss Duernstein--it was like a castle! All breakfasts were terrific (lots of selection, hearty options, and the best breads I've had anywhere). Furthermore, the actual route was terrific--safe, low traffic and chockful of spectacular views! I was originally concerned that we started out on cobblestones and dirt paths for a bit in Passau, but the bikes were so sturdy and had such good suspension that didn't matter. I felt in control of the ride at all times. Most of the time, public restrooms were available on the route and were adequately spaced out so I only needed to do the "hide behind a tree or bush" thing a couple of times.
A couple of warnings to future travelers: 1) We went in April, and only the final hotel (in Vienna) had legitimate air conditioning (per North American standards). It was unexpectedly warm in the evenings, and we wished we had brought a fan (only the first hotel in Passau provided us with one), particularly since all hotel beds had thick duvets for covers. I can't imagine what it'd be like for people traveling during the summer. 2) Do some research before arriving in Melk. This was the only place we got lost and had to use our cellphones for GPS because the cue sheets weren't specific to our particular circumstances (they covered only instructions for people staying at certain hotels there, which we were not). But we did eventually find our way, and we're already thinking about planning our next trip!