We embarked from Southampton on the Arcadia. It's a great ship - not huge and also no children - although as a result probably an "army" of disability scooters - not really a big problem. Arcadia has recently been refitted - and mostly the ship seemed in very good order. The wooden balcony rails need re-varnishing but other than that all pretty good.
The cruise itself was excellent -the ports of call: Zeebrugge, Gdynia /Gdansk, Klaepida, St.Petersburg, Tallinn, Copenhagen. A very good mixed bag with of course the Jewel in the Crown being St. Petersburg (2 full days in port).
We used P&O for the tours in Gdynia /Gdansk and Tallinn - both well organised. The Tallinn one was rather short but as my wife is mobility impaired it was termed a "simple" tour - which it was. Also, I would say Tallinn is overrun by cruise-ships and there's very little peace and quiet from the souvenir shops and stalls in the small and quaint old-town. St. Petersburg was brilliant. We had arranged tours ourselves through Allah Tours - a local Russian company. They were superb - no worries about Visas or anything the organisation and the programme for the 2 days was 5-Star including cooked lunches in local restaurants.