We booked this Baltic Sea cruise because of the itinerary, especially because it spent 3 days in St. Petersburg and included a stop in Riga, Latvia (other cruise lines did not stop here). Having been on many cruises, on other cruise lines, here's my impression about RCCL Serenade of the Seas:
Check-in and embarkation is a breeze providing you have done all of the registration online and printed your Sea Pass prior to boarding. RCCL wants you to use their mobile app for many things, like setting up your profile and account, booking activities and restaurants, etc. The problem is the app doesn't work well and can be frustrating to use.
Within the first hour of boarding, we were approached no less than 6 times about purchasing either one of the dining packages or the beverage package. We did end up purchasing the 5-dinner package, which allowed us to dine in the 3 specialty restaurants. During the cruise we were also told we could use one of our dinners for the Champagne Brunch and Galley Tour on the one sea day, which we did (it was very nice). Booking the specialty restaurants in advance is more expensive than waiting until you get on board, so wait. These restaurants were never full for the times we ate there so booking onboard should not be a problem.
Our state room had not been converted from one large bed to the two twin beds we had requested in advance; that was taken care of after we had boarded and while we were at lunch. The stateroom was fairly roomy for two people, plenty of closet & storage space. Our suitcases fit easily under our beds, but we never had bedskirts on our beds for the entire voyage - only on the next to last day did they appear - so you could see everything stowed under the beds. Not a big deal, but one of the many "scratch your head and wonder why" moments on this cruise.
There are NO amenities provided in the bathroom other than the combination body wash/shampoo dispenser in the shower. You need to bring your own shampoo/conditioner, body lotion, cotton swabs, etc. No bathrobes are provided either. Our room steward was OK, not great. He remembered to bring us fresh ice every day, but on more than one occasion did not leave us towels in the bathroom.