My first time renting an apartment instead of a hotel room, so a short booking to test the water as I was passing through.
The flat:
It lived up to my expectations from the pictures - large living room with small kitchen area, bedroom with huge double bed, en-suite bathroom with separate bath & enclosed shower (no wet floors!) Living and bed rooms each have their own a/c which worked well. Being on the 15th floor there's a good view to the west (though not of any of the more iconic sites of Bangkok which are a few miles away.) I didn't try the pool and gym facilities but they looked clean. Wifi (private, not shared with other flats) worked well.
Note: Key pickup is from a non-resident caretaker so you need to agree the time in advance, or coordinate by phone.
Transport:
A short walk to the Siam shopping district, a bit longer to the nearest skytrain station. You'd need a taxi from the station (and clear directions for the driver) if carrying luggage. My ride to the airport was no problem - I just phoned down and the front desk had a taxi ready in a few minutes.
(PS if you don't like traffic jams, you can easily get to the historic part of Bangkok by khlong boat - the nearest stop on the Saen Seb canal is visible from the window.)