Buenos Aires is an incredible, life-changing, big bustling european city. However, there is no reason to go to this incredible country and spend all of your time with other students from the United States. There are a few opportunities to connect with local people if you explore outside of your comfort zone but I would highly recommend doing an exchange or taking classes at Belgrano instead. The professors are nice and everyone has the best of intentions but I feel that it would have been much better for my Spanish if I hadn't been surrounded by other English speakers constantly. I met many students from other programs who also were in a similar situation. Host families always vary but essentially many of the programs offer the same services.
My recommendation is to choose a program provider that doesn't include trips. You can always plan the same trips on your own. Usually much more affordably as well. This way you can go when you want to go, where you want to go and you can go with the people you want to! On these planned trips you are usually grouped in on a massive bus full of other american students.
Otherwise, CEA was lovely. I wouldn't regret spending a semester in Argentina for a second. I only regret not taking a bigger risk and doing an exchange or direct enroll program with other spanish speaking students.