We took the tour that visited city highlights, had a nice lunch at a manor house in the countryside, and went to Porvoo. We weren't as delighted with Porvoo as we thought we'd be, and Helsinki wasn't as beautiful as some of the other cities on our itinerary.
A lovely, crowded city with massive and stately structures - a bit too "decorative" for our tastes. The Hermitage is amazing as far as its collection goes - but why no AC? Isn't the lack of air conditioning bad for all the treasures? We went on a private tour because we wanted to visit the Choral Synagogue - which wasn't a site to see on any of the ship's excursions.
Riga is interesting to see - its beautiful street near the pier, its old parts, its history. It was interesting to take the tour of its (terrible) Jewish history - and to see it up close.