I am on a commuting contract in Japan and I have been living in Bangkok for the last 2 years. Besides Korea, I would say that BKK is the easiest commute there is.
Bangkok it cheap and there is always stuff to do, but after a while, it can start to wear on you. Taxis with no seatbelts, general disregard for anything safe, traffic, etc.
All in all I am relatively happy in Thailand. There are good and bad things, but for the near term, it fits the purpose of residing close to Japan. It's next to impossible to buy a house, but apartments and condos are easy. Prices can be high inside the city, but are very affordable once you get outside.
Be aware that you are limited to 90 days stay every 6 month period unless you have a non-immigrant visa. For you there would be no problem as you are going to Japan to work, but you would have to come up with some kind of plan for the rest of your family. As for me, my wife is Thai and I have a visa based on our marriage.