I have traveled to Vietnam 20+ times in the last ~5 years. All personal trips ranging from 4 days to 3 weeks.

I would say that the mark ups on places like the Park Hyatt etc over there don't make sense.

I find the hotels in the 50 to 70 dollar range to range from perfectly fine to amazing.

Plus, in the off season there are some deals in the beach towns that can't be beat in some of the smaller beach towns like Phan Thiet. I stayed at a great hotel for like 30 bucks a night, and since it was "off season" the prices on the menu got cut in half. Which made beers 50 cents USD, and dinner 4USD.

There are some great values and great properties to be had in Vietnam for sure.

Also, if you really want to do some more exotic luxury brands lots of top tier Korean hotels have properties in Vietnam as well if you want to try a different kind of 5 star experience.

Although I would say overall its not worth it.