Which itinerary are you doing in the Baltic? We did a 12 night Baltic last summer on the Adventure out of Southampton, and it was wonderful! The ports were amazing, we loved our server in the dining room, the food was great, and the rest of the crew was lots of fun.
There were only 2 drawbacks, one RCCL couldn't do anything about, and one was just a "feature" of the ship. The weather was cold for the trip, we had rain in Oslo and St. Petersburg, and the temperatures were pretty chilly, so something to keep in mind. The other drawback was that on the Adventure, the Balcony staterooms say they sleep 4, but that's accomodated by the king main bed (split into 2 twins if desired) and then a double fold out couch. My kiddos weren't really happy about having to share a bed, so something to think about if you're sailing the Adventure or any of her class and want a balcony room.
As for the trip itself, it was great, we booked tours on our own everywhere we went, 3 ports with Alla Tours (
www.alla-tour.com): Talinn, St. Petersburg and Helsinki, we did the HoHo bus in Copenhagen (in retrospect, we wouldn't have done this, it doesn't run often enough to really be a good option) and tours in Oslo and Brugges which is what we did in Zebrugge.
Highly recommend the trip, we all loved it and the ports are so amazing, St. Petersburg was absolutely beautiful, and we ended up seeing more than our tablemates who had booked through the ship, for less money!
In any case, the Adventure is sailing that itinerary next summer as well, so if you're booking on her, and have questions, let me know, I'll answer them as best I can.