Three of us are going on the Viking cruise of the Black sea from Odessa to Kiev. From there we want to make a stop in Moscow. Need to figure out which of many options to select.

Orbitz lists 4 carriers with direct flights on that route--Aeroflot, Aerosvit, S7, and Ukraine. Does anyone have experience with any of these carriers in general and particularly on this route to give me advice on which to choose? My research on some airline review websites suggests that Aerosvit is the worst of the bunch, Ukraine a bit better, especially on this route, S7 and Aeroflot best of the options. Does that comport with any personal experiences out there?

Another search turned up Air Baltic, the Latvian carrier, which is not rated highly (opinions on that also desired) but has lower rates for your misery and offers us a very interesting possibility--an 8 and 1/2 hour layover in Riga. DH was born in Riga and we've recently begun to think of going there. Could be a golden opportunity. Problem with this is determining how much time we could actually spend in the city with such a layover. Looks like a cab ride to city might take as little as 15 min. each way/ If that's really true and we arrive on time (again, opinions on Air Baltic performance sought) it sounds like we could work it out. Does anyone know of any restrictions the airline might put on such layovers? We used to do it a lot out of AMS, but AMS and Riga may have different rules on such things. Would there be anything prohibiting us from leaving the airport during the layover? Is security at the airport awful such that we might not be able to get through in an hour or so, further cutting into our tour time?

Finally if flying proves problematic, there is a 14+ hour train ride without changes between the two cities. Has anyone here done that? The bahn.de site seems to say that it's only 2nd class and doesn't show any info about sleeping arrangements. Do you actually sit up the entire night? Is there another site I should consult? Raileurope provides no info at all.

Sorry, lots of questions but answers to any of them would be very much appreciated. Thanks.