I realize I'm late in my review (we sailed in October), but since I looked to this site for information before we (my mother, my sister and me) sailed, I thought I'd add my review to the rest.
First why the cruise. Although my mother and I had been on a previous Mediterranean cruise and have travelled throughout Europe, this was my sister's first trip to Europe and my mother has difficulty in walking, so we decided on this cruise. Personally, I prefer to travel by land and stay in a any one place for several days vs. the "If it's Tuesday it must be Venice" type of travelling, but it sure beats not going at all!
Although many reviews discuss the individual ports visited, I will skip those. I think it a matter of personal preference where you want to go and what you want do. Basically you need to do your research beforehand to determine what you want to see in each port.