I stayed at the JW Marriott, Bangkok last November. (Using my Marriott rewards points) Service is superior. Food is delicious. The staff is friendly and accommodating. This JW is one of the most beautiful hotels I've ever stayed in. If you ever get the chance to go to Bangkok, make the JW Marriott your home away from home.
I concur - JW is right in the heart of one of the more lively parts of the city. I also recommend the new Courtyard hotel in Bangkok - large comfortable rooms, nice pool, great staff and free tuk tuk rides to the sky train - in fact, the nicest Courtyard in all my travels !!!