FWIW I got 34.047 from an AEON ATM in Seacon Square on the same day (Friday, August 21, 2009). I’m using a Visa debit card. Mastercard might be using DCC which results in lower exchange rates. Also some might have hidden fees. It can be challenging to compare rates without all the details. Most reports on TV show AEON giving the IER rate, as do GSB.

Agree Superrich is great if you have $100 bills, almost as good as my ATM rate. When changing currency here many recommend writing down the serial numbers on the bills, adding the last one in full view of the clerk. This discourages the counterfeit bill substitution scam, which has been reported as occurring in Thailand (and other countries). I have never seen any bad reports about Superrrich.