Withdraw Cash from Thai ATM: Comparison Between 3 Banks

I always prefer to bring cash with me when I travel and exchange it in loco as it is the most convenient way to get the local currency. But sometimes I just can’t organize in time the shipment of several containers with all the money that I usually need. In these cases I rely on my credit card and I found out that there are significant discrepancies among the exchange rates applied by the Thai banks.