I stayed in the Banyon Tree for three nights and arrived after a 10 hour flight into Bangkok. I emailed the hotel a few days earlier to tell them that I would be arriving early and if there are available rooms to hold one for me. When arriving at the hotel, it was around 7am local time. I was told at check in I would have to pay a full days rate in order to access the room or just wait in reception until 2pm. If they didn't have available rooms I would understand having to pay a premium in order to get a room prepared but they did and I felt they were not sympathetic to our situation.
After about an hour and a half and some negotiating they allowed us into our room and the Banyan Tree experience got a whole lot better. We stayed on the 48th floor in a deluxe room and the views of the city are amazing. The rooms were immaculate and looked just like the images on the website. The hotel also contains the much hyped Vertigo restaurant which is something you should experience if you stay here. The pool is located on the 21st floor and so are gym facilities which were both of an extremely high standard.
The hotel itself is located in a business district but is about 10 - 15 minutes walk from the nearest BTS Station (Sala Deng) but they do provide a shuttle service every hour.
Overall I would still recommend this hotel but the arrival experience could be improved and not use it as a chance to upsell. If it wasn't for that I would have easily awarded this hotel 5 points.