We did the Baltic and on to Southampton on Whisper and enjoyed our first experience with Silversea, although the food was all very Italian based, which can become tiresome. We found Seabourn to have a greater selection on their menus and wines were also a little better class.
Having also completed over 70 days cruising with Seabourn the comparison was interesting to say the least.
Port excursions are expensive on any 6 star vessel and we were introduced to private tours, by meeting fellow passengers on line prior to departure through Cruise Critic. We enjoyed smaller tours groups and very informative Guides through TJ Tours in St Petersburg.