Not familiar with Berkely. UCLA is convenient if you want to take classes at night time and if you plan on taking 3 classes per term, it's about 400+ cheaper (700 for each class at UCLA *3 = 2100, CSULA is about 2500 per quarter). That's it. CSULA offer various workshops, mock interviews, and guest speakers. Not to also mention, an informal linkage to Western DO. In terms of difficulty, they are about similar. UCLAExtension is graded mainly on quizzes and exams only, while at CSULA, you would have to do lab reports, presentations or papers on top of the quizzes and exams.