All else being equal, VietJet Air does have newer planes, cheaper tickets and that "pizzazz" of a new, hip airline. So if all goes according to schedule and you're traveling light, then sure all is great.

But how often do things go well? And what happens when they don't?

VietJet has a tendency to completely meltdown when it comes to IRROPs. VN sometimes isn't much better, but at least they have a large fleet and multiple frequencies to fall back on. VietJet will just cancel and call it a day... whether they help you before going home is an unknown.

Glad you liked your experience with VietJet, just don't get caught unaware.