Hi and Welcome to GMAT Club.
This question seems somewhat familiar... I definitely see the allure of Miami in the winter vs. Chicago. I think part of the answer is what you are planning to get out of the EMBA.
Since you are mentioning that it is "cheaper" and "expensive", I take it you are paying for the EMBA yourself and perhaps fair to say you are going to change your employment? My guess is you would want to network with some folks and perhaps even drop in on some of the recruiting events (though those are unlikely to convert into anything specific right there but it may be a good networking opportunity afterall - you won't know unless you try I guess).
The other benefit of Evanston is that you are at the home base vs. a few rented classrooms in Miami at
the shared co-working space. Not a big deal per se but you get access to the campus, events, games, better facilities, and ability to audit drop in on certain classes, lecture series, tailgating, etc I feel there are potentially a number of benefits. Not sure where you are based and how much more it will be to fly to MIA/FLL vs. ORD/MDW but I find ORD to be cheaper from most locations, esp during spring break, holidays and other times, though there is a reason nobody flies to Chicago in March.
Bottom line - it is hard to make a recommendation not knowing the dollar amount. I would recommend calculating it out and then weighing the above benefits (they are intangible and speculative but perhaps there is a way - could your first EMBA project!
)
Congrats on getting in and good luck!