Test today:
38,000 COP @ midmarket exchange rate of 3328.50.
Chase Sapphire Preferred: 11.40
Discover IT: 11.34
So for all the Discover bashing going on, I thought this was an interesting point. I made the same purchase yesterday on Discover and got the exact same exchange rate, so I'm not sure what day or formula they use.
All that being said, I've found that here in Colombia at least, Discover IT is accepted everywhere that Visa is, and the exchange rate seems to be the same or better.
Cheers