The man in seat 61 seems to say, as of mid-December 2011, that the train trips to/from Istanbul are better via Bucharest than Sofia and Beograd, at this point in time. I have a LOT of faith in his experience, but I'm curious what others' experiences might also be. Also, the Dec 2011 Thomas Cook European Rail Timetable does note that the sleeper or couchette cars on the overnight trains to/from Istanbul via Beograd are "reported as not running most nights". Which increases my curiosity about the reliability of booking either the inbound or the outbound leg of an Istanbul trip from, say, Vienna or Prague, via Beograd. Anyone have anything else to add? Any and all answers greatly appreciated!
the quality is about the same - maybe depending on the country of the train (romania vs. bulgaria) the bulgarian train is slightly better in my opinion, but its eastern european train ride overnight, so you can expect full compartment, with guys snoring, possibly smelly feet, etc, but not too bad. The trip from Vienna or Prague is longer, and you'll likely ride with similar crowd, so i'd not expect anything hugely better.