I can't be of much help on the international student thing, but I would say that community college classes are viewed with less regard from some schools, and many schools will not accept CC credits, will only accept so many, or say no CC credits for math/science classes. Therefore, you would need to make sure the schools you apply to will accept CC credits. If there is a financial or other reason you specifically did not do the University thing, I would probably explain that to the admissions committee. From experience, I can say that the calibur of education is entirely different. I've taken all of my units at the University of Arizona, but I took physics with lab over the summer at a CC (mainly because I didn't have time to take it during the year), and it was a joke as far as the expectations, the teachers' knowledge and abilities, etc. It took minimal effort to get a 4.0 in physics over the summer, and EXTREME effort to get a 4.0 at the U during the school year (both of which I have done).