I have taken the overnight train to Cordoba several times, in a private room sleeper (camarote). It's run by Ferrocentral, the same company that runs the train to Tucuman. This is a reliable private company, unlike Ferrobaires which is run by the province of BA and quite a mess. The sleeping car rooms on the Cordoba train were clean with their own wash basis. Small closet for coats. A lot of storage space and upper and lower berths with comfortable mattresses, clean sheets and blankets. Friendly crew. Dining car meals were not great. If you have an independent spirit and can ignore the prejudices of middle class Argentines who usually think all trains in Argentina are uncivilized, by all means take the train. Personally I consider buses, no matter how "luxurious", to be claustrophobic and miserable. I'd far rather be in my own comfortable room and be able to get up, go to the dining-car, walk around get off at stations. I think the rooms can be made en suite, i.e. there is a connecting door so if you pay for two you should have access to the other without going out into the hall. As for someone's comparison to Amtrak -- sorry but AMTRAK runs some very impressive long distance trains with double decker sightseer cars, rooms with their own showers or economy rooms with showers down the hall. Many trains now have WIFI and standards are a LOT LOT LOT better than any train in Argentina but I know having said that someone will tell me it isn't true. I doubt they have ridden on almost every AMTRAK line all over the US, though, as I have.