It seems like I'm a bit late to the party. I thought I had time to book this new Rhone cruise because all of the sailings were labeled "available" rather than "limited". The fact is that April, August, and October are nearly sold out. We had been looking at the August sailing. But, only category 1 is available with an established wait list for the other categories. If anyone has used that category I would love to know if there was engine noise to contend with and how claustrophobic you felt. I imagine the tiny windows would mean a dark room.
BTW - I have gone on the Danube cruise with MS Inspire. Their category 3 has a two level 225 square feet room as opposed to MS Emerald's category 3, one level, with just 150 square feet. Not all of the riverboats are the same.