We took this cruise August, 2011(St. Petersburg to Moscow). First, let me say that I have only been on 2 ocean cruises prior to this Viking cruise and cruising is not my preferred vacation style. That being said, we were invited by dear friends to join them on this river cruise in Russia. I read the various trip reports and I am amazed how my opinion differs from many reviewers.
The ship I was on (Pakhomov) looks like it has been renamed in 2012 to Ingva. On other cruise lines there appear to be a variety of nationalities on board - but our ship was exclusively Americans. Given the way you are herded back and forth on buses - you could actually spend 13 days in Russia and never speak to anyone but an American (unless of course you get away from the ship/bus and make your own way - which we did).
My companions and I found the food barely tolerable. When in major cities (St. Petersburg and Moscow) we only ate breakfast on the ship. Although my expectations were low - they were not low enough and paying for our meals was the least of our issues.
My #1 complaint is the extreme distance river cruise ships have to dock from the major ports. This is a complete waste of your vacation time and sitting in gridlocked traffic in Moscow for hours will make you scream. We quickly learned the excellent St. Petersburg and Moscow metro systems and used the ship more as just a place to sleep.
The hardest part of the trip was the 5 day cruise between major cities. I though river cruising would be smooth - however when we went across major lakes - the ship rocked so hard and created such loud noise in our cabin (#428) we were awake most of the night.
Finally, do NOT take the airport transfer ripoff. In Moscow, they wanted us to board the bus at 8am for a 2pm flight. We skipped the bus ($120) and took a 10:30am taxi ($45) to the airport and arrived easily in time for the flight. We ran into others from our ship that had been sitting in the airport for 5 HOURS.
If you really want to experience Russia - don't take this river cruise. Get a good travel agent with local contacts and get out to meet the Russian people. They are amazing....