It all depends on what you are looking for on a holiday or in retirement.
For some, Thailand is ideal, for others Viet Nam wins hands down.
Horses for courses, as they say.
If I was a decade or so younger, and healthier, I would be in Viet Nam now.
But, 15 years ago, Thailand was the easiest and best option for me - but since then, Viet Nam has moved ahead on many fronts.