I flew PB Air (9Q) BKK(Don Maung)-DAD a couple of years ago. It was a pretty decent flight. The Thai check-in agent gave me preferential treatement, presumably because I'm American (not fair to the Vietnamese passengers but who am I to complain . It was a ERJ-145, aparently well maintained and in any case was clean and looked new. The cabin crew were very friendly and efficent. Meal was served. The pilot seemed competent, as far as I could tell anyway. In all, a professional operation as far as ERJ-145's go. Since AFIK they are the only non-stop option DAD-BKK, they are just fine and it is not really worth an unnecessary connection to fly anyone else.