Train was delayed by 50 minutes, which feels like an eternity at 4am, but all in all can’t be helped. Also, during our entire journey nobody checked our tickets, we were slightly confused upon arrival at the station as there was nobody to give us any instructions, though it is fairly straightforward. Would advise for 12Go to perhaps add a slight bit more info regarding going early morning - IE train platforms, etc, but again not a massive problem!
All in all once the train arrived we were lucky to have a cabin to ourselves and slept soundly most of the journey, could not fault as soon as we boarded. All in all a good experience, just a couple of tiny hiccups which if you don’t need handholding I’m sure are okay.
Got from Nha Trang to Da Nang but were delayed an hour. Additionally we couldn't sleep due to the cockroach infestation in our first class cabin, and at 5am several Vietnamese began smoking and eating durian. We had to move up the train to the regular second-class seats which were much more comfortable - sadly no refund is on offer.
The train was 3h delayed and the rooms had very strong AC. The bathrooms were decent - relatively clean and with normal toilets. You need to bring your own toilet paper. The seats we chose were not available so we got different ones. It might be better to book directly with the railway to know in advance which seats are booked. The map in 12go showed all seats as available when it was not the case.
Train was slightly late but not terribly. The beds were fine but we expected slightly more from first class. Sheets were used from previous customers and not cleaned at all. There were used baby nappies stuffed into the luggage compartment above the bed. Toilets weren't great, but they existed at least.
If you don't expect much, then you'll probably have an okay time.