So beach holiday...

Horror stories of the beach in Nha Trang? The beach there is great, IMO.

Been to Mui Ne once. I didn't really even see a beach there. Maybe I was there at a tidal high time of the month? I would not recommend going to Mui Ne if you're looking for a beach holiday. Found this random website with some photos (note the 2011 date) : https://leaveyourdailyhell.com/2011/...-travel-guide/

Never been to Phu Quoc. Pictures look nice, but my friends tell me it's really been getting developed over the past many years. This is on my list of places to visit.

If you've got Mui Ne and Nha Trang on your list, then how about Quy Nhon? I haven't been there, so I cannot comment on the beach conditions.