Hi,
Depending on your expectations/spending habits, I think 20k is an OK funding for Orlando. In general, I would say that Orlando is not an expensive city. You will have a stipend around $1600 per month and you pay $1000 for rent(1 bedroom apartment)+ bills and try to make your living with the rest of money. I know some married international students with the same amount of funding and they are able to continue. Of course, you try to live on bare minimum but it is what the graduate life is about.
I know people from the Security Studies program and they are generally happy about it. Of course the program is neither good ranked nor reputable but they say that the faculty is pretty good and the student/faculty ratio is very low. They say that the faculty cares about the students. Also, Orlando is home to many intelligence/military related companies(e.g. Lockheed martin) if it is your thing.
In summary, my perception of UCF is positive and I would suggest you go there if it is your best choice.