OP, thanks for starting this thread, as I had not seen it and put up a thread in the viking section regarding this topic. (I am wondering if people there are more viking centric vs people in the princess thread being more princess centric...)
I know that cruising really isn't the best way to 'see' the countries, but it is the most convenient. So I am most interested in the places and excursions. I have been on princess, but not viking. What appealed to me on viking was the smallness, I figured it was just easier when you have less people to get on and off. Also, having no kids. (The princess baltic cruise is june 30, so while there probably won't be many children, it is still vacation time). Plus I thought having everything included would make things easy. However, when I looked, not sure the included excursions would be the ones I want to do, so this might make things more equal.
I like that viking has a historian on board, I want to learn about the places. OTH, after reading the thread, we also like the evening entertainment on princess and hearing viking is lacking might be an issue?
Really appreciate the comments here. While I think viking is about 25-33% more, I am happy to pay for it IF IT IS WORTH IT. But I am looking for the best experience, and would be unhappy to find out that I am paying a premium but I would be just as happy or happier on princess!
Also, should note that viking starts and ends in stockholm and bergen, 2 non direct flights, while princess starts ends in london, easy to get to directly.