Data point
I had to be in Bangkok, and Koh Samui in and out of Thailand 4-5 times during a 15 day period. The Truemove kiosk at the airport was easy to use and I picked up a plan that covered the time I needed. It was a little confusing at first figuring out what I wanted but once I decided the rest of the process was quick. The guys at the desk load the base sim for the plan you want and then add the add ons that give you unlimited data etc.
The updates and info I got texted to me from True move was all in Thai and got a little old, but it was just advertising. The access worked. Google maps and navigation worked well in almost all situations. I had some slow downs in BKK. I would use it again.