I just came back from a trip to Vietnam and wanted to give a quick report as I do not plan on returning in the foreseeable future.
The blackjack in Ho Chi Minh City, where I stayed, is offered at several different 5 star hotels. The games are virtual with a dealer who uses a computer screen to deal and shuffle virtually, some casinos even having the player use regular hand signals which are interpreted by the real-life dealer and input into the computers.
That said, there ARE countable games in the city, and the rules are quite favorable. One HCMC casino I visited had S17, DA2, LS, 6 deck, 5/6 penetration (still virtual), and perhaps even RSA, I am not sure on that last rule. Table min/max change and vary from casino to casino, but seem to hover at $10-$400, in U.S. dollars, NOT Vietnamese Dong.
I understand there is quite a large casino in Ho Tram Beach where the dealers use tangible cards. I did not have a chance to visit so I cannot speak on the conditions at this casino.

I will be taking trips to other Southeast Asian countries and evaluating their blackjack conditions. If there is interest, let me know, and I will continue reporting. Thailand and Indonesia have no games. Singapore has two very nice casinos, no good blackjack opportunities worth reporting.