It was our first cruise, and this experience made us cruise lovers!
Viking Cruise is all-inclusive cruise line, so our cruise was quite comfortable, but level of luxury was not too much. It is suitable for people who like to enjoy not luxurious floating but exploring. You can have enough time to see around at each port, ports were sometimes a bit far from city center though. (Especially in St.Petersburg, there was no public transportation around the port, and it took more than 30 minutes from the port to the city by car. I personally took VISA and stayed at a hotel for two nights, and it was a good decision.)
I stayed Deluxe Veranda Stateroom. It seems to be smaller than other luxurious cruise lines one, but it was enough. My husband and I often went out to see entertainment and play board games in public area, so we didn't stay at cabin for so long. Although we were actually much younger than other guests, we could enjoy the most of their entertainment programs.
Buildings were beautiful, (most) people were surprisingly kind, and FOOD WAS AMAZING. Fish eggs look disgusting? You should try!
Traveling St.Petersburg was actually not so difficult. I strongly recommend to take VISA beforehand and explore by yourself.