I am happy to tell you about my experience with CIEE - mainly because I absolutely loved my study abroad experience! I studied at the Global Institute in London for Spring Block III and Summer Block I. This was because UCSD is on the quarter system and those two blocks combined fit UCSD's Spring quarter almost exactly. This allowed me to study abroad for the single quarter which is what I wanted (not a semester). I was unable to find this with any other program.
UCSD evaluated the classes I took while abroad as counting as upper division courses, however, I do not know exactly how they will count for my major (Literature/Writing) yet because that only occurs after I return to school and submit documents this coming Fall quarter.
My overall experience while in London was amazing! It was my first time living in the middle of a big city, but the staff at the Global Institute made the transition and adjustment much easier for me. They were always available for me to talk to and answered any questions I had promptly. They were even good about recommending things such as places to eat, things to do/see, etc. The student accommodation (King's Cross Chapter) was also very nice.
As for the academics, I feel that the classes I took in London were equal to any class I could take at UCSD. The classes were challenging, but interesting; fast-paced, but didn't leave me in the dust (as long as I was diligent about doing the reading/assignments). My teachers were amazing, passionate, and engaging. They were always willing to talk to me about the class, an assignment, or anything related to the subject that I was interested in. The structure of the class (being in an English teaching style) took some getting used to, but it was not a hard adjustment. Being a Literature/Writing major, I did not have too much trouble with the multiple essays that were required for each class, but I know that was not the case for everyone else in my class.
I went to London for school and for fun, and both aspects far exceeded my expectations.