well if coming by plane not sure there are ATM'S before passport control. Definitely bureau de change. I'd be careful and bring the required amount in cash.
go with AIA and I'm not even with them. But best thai local insurance company. Been here 6 years and no one will cover you for more than 100,000 USD. only AIA will
axa I have London. Axa thailand is a rep office only only. If you have insurance for 100,000 usd it works. Try getting comprehensive cover for 2.5 million USD they'll show you the door and say sorry NO WAY