As for the ship and the crew, they were very professional and accommodating. The food and service were excellent with plenty of variety including local dishes. The guides were exceptional, all native Russians, mostly from St. Petersburg. Their English was excellent and, along with local guides, they provided us with reams of information about Russian history up to the current day. They were open about their recent history and the transition from Soviet to modern day Russia. After may years of propaganda on both sides of the Iron Curtain, it was refreshing to experience the openness.
We were impressed with how clean and friendly both Moscow and St. Petersburg were. You've read about the heat and the smog. That was a challenge but we worked around it, thanks to an air conditioned boat and tour buses.
This is an education trip, not one that you kick back and snooze ... although you can to that, but you would miss the best parts. When the trip is over, you brain is full and needs a rest. At least mine does.
Not everything was perfect. Viking advertises WiFi. It worked sporadically and when it did, the bandwidth was very narrow. I took my new iPad which does not have an Ethernet connection, which was a problem so I had less access than those with net books or laptops. I wish Viking was fix the connectivity or set expectations better.
Several people complained of feeling ill. Nothing serious but certainly took the fun out of the trip. We're not sure if someone brought a virus on board or maybe the ships water wasn't purified enough. Although hand cleansing stations were available, Viking was not as diligent as other lines in encouraging their use. I don't know if that would have helped.
All in all, the experience was well worth the money. It gets four thumbs up from us.