I did about 30 flight legs on Bangkok Airways in the last few years. The airline calls itself Asia’s Boutique Airline with a focus on quality domestic and international air travel.
Every passenger is entitled to visit Bangkok Airways own lounges where coffee, tee, water and orange juice is offered for free. Wifi is also available for everybody. Inflight service still consists of usually a small hot meal and a sweet item which is not to be found on any other thai carrier. Soft drinks are also offered. Crews are friendly, well trained and safety conscious.
If you are flying out of Suvarnabhumi airport in Bangkok I highly recommend web check-in as lines can be rather long (especially early morning). A good solid product which has not changed much over the years and still the airline of my choice for thai domestic and regional destinations.