You'll need a LotusMiles account.
Trying to manage flights on VN online can be...umm...time consuming. Downright impossible without a LotusMiles account. That said, booking flights was painless.
Domestic flights on VN I experienced were on rather shoddy aircraft in 2016 (A320s). That said, it appears they have since retired them. I saw one A320 with a VietJet engine cowl, while sitting in a very tired A320 with several broken seatbelts and broken emergency floor lighting. Legally, not airworthy. Which probably explains why VN's hopes of establishing direct flights to the USA by the end of 2017 are on hold.
Service was outstanding. But aircraft are switched out at the last minute depending on loads. I learned the hard way that VN will not fly a half-full 787. I got pushed to an A321 and didn't get to take my first Dreamliner ride. (grrrrr)
VietJet (and from what I could tell, every other airline in the country) use the term "schedule" rather loosely. VN is definitely the only carrier that placed any importance on timeliness, but their tickets are more expensive. Domestic flights are dirt cheap on alternative carriers, however. If you miss a connection, you may be better off just buying another ticket rather than expect customer service to do the right thing.
Cheapest way to get from Vietnam to the US is via China. Easy and surprisingly seamless.
If you've not been to Vietnam yet, you can practice crossing Vietnamese streets by simply wading across shallow rivers. Wade in and don't stop moving until you reach the other side!
Lots of internet restrictions, as far as what websites could be accessed. I don't recall specifically about FT, but Facebook and most other chat forums were blocked.
No, the country is not flooded with billboards and banners for KFC.
That's not Colonel Sanders.