Just returned from a super Baltic cruise on the Star Princess at the beginning of July. It wasn't our first cruising experience but it was certainly the best so far, although there is so much to do and see (7 ports and 7 counties and 7 currencies in 10 days) that you probably need a holiday to recover afterwards!
The positives were as follows:
The port talks by John Lawrence were extremely good especially if, as well as the historical context of each place, you are going to explore independently and so need to know where to catch the hop on/hop off buses etc. They undoubtedly added enormously to the overall experience. If you miss any of the talks (a couple are scheduled as soon as you return to the ship from the last port!) you can see them on the ship's TV system later on. Tip - before we went, we looked at quite a lot of the Baltic cruise reviews on Cruise Critic, some of which contained excellent advice about what to see, how to get to places etc. Highly recommended.
Disembarkation at each port is very quick and simple. We had heard that, on some ships, people not taking the ship's own tours are held back but this is certainly NOT the case on the Star Princess. Tip - don't delay getting off in St Petersburg as the immigration/passport queues soon get quite long.
Anytime dining - our first experience of it - was great. We never had any delays and, each night, could choose if we wanted to share a table or sit on our own. The dining room staff were first class.
Cabin/Stateroom - very good with plenty of space. I hadn't expected a 'free' safe (very easy to use too) and quite so much hanging space. Bathroom small but completely adequate.
On the other hand, if we had to suggest any areas for improvement, they would be as follows:
If only one or two of the port stops could be a little longer. For example, Tallinn and Oslo in particular. On several occasions, the announcements suggested the ship was going to have to race to hit the next port on time but, in actual fact, we cruised along at a very stately pace.
The entertainment shows were very glitzy but quite short - often 40-50mins and some of the singers were not brilliant. On the other hand, the dancers were generally very good and sometimes so energetic they were quite exhausting to watch!
It would have been good to have a pool reserved for adults (or perhaps a time for adult swimming) as sometimes groups of children made it hard to swim in the smallish pools.
Formal nights - Having at least taken a suit to wear, I was surprised how many people didn't bother to dress up on the two formal nights. I didn't see any evidence of the restaurant staff restricting entrance to the dining rooms to those who were still in their shorts.
All through the cruise, a fat 'tasting' chef kept waddling round the various dining rooms asking people if everything was OK. Since there were plenty of other staff on hand to sort out problems, we felt he did not add any value and, in the end, found him quite irritating!
Movies under the Stars - went to watch a good film one evening but found the experience ruined by groups of children shouting and larking around. No staff around to watch out for such things.
Navigation info - the ship's TV system is supposed to enable you to see where you are at any time. In practice, it is very poor at doing this and the system needs a radical review to, say, come up to airline standards.
Finally, a tip about currency. Don't worry about taking lots of currencies or even converting money on the ship (poor rates of exchange). If you have some Dollars and/or Euros with you, you will be fine in most places. If you really need local currency then ATMs are available everywhere and, of course, most shops will accept credit cards etc.