I trained here for a year and I loved it. Can't wait to re-register, in fact.
The training regimen is very authentic and there's a lot of emphasis on sparring, which means you actually learn how to *use* the techniques taught to you by the instructor.
Evening classes can get a little crowded sometimes (depending on the weather and time of year), but Saturdays were my favorite: a good number of people always show up on Saturdays and there is more emphasis on sparring.
So whether you're experienced in Muay-Thai or want to learn it for the first time, you should definitely consider Daosawan. Prices are also some of the most reasonable in the city.