Mills is not cohort-based, your courses are with undergrad in lecture, post-bacc's in lab.
(sorry for typos, posting from phone)
Not sure if it's too late to chime in, but just in case:
It's actually the opposite-- Mills is most definitely a cohort program--the lectures are for post-bacs only, though undergrads can petition if they have extenuating circumstances to get into the post-bac lectures. There might be one or two in each lecture at most (there were one or two undergrads in my physics class, and none in biology or o-chem while I was there). The labs do mix undergrads and post-bacs, but the post-bacs almost always work with one another; generally you work with students you know, and undergrads tend to know undergrads and post-bacs tend to know the post-bacs.
Personally I loved Mills, and I credit my success on the MCAT and in getting accepted into medical school to Mills. Could I have done as well at SFSU? Possibly--I really don't know. I like that the formal post-bac program (I think that's the only program offered now) is a cohort program like Mills--I wanted to be surrounded by others who were in my situation, and not have undergrads around in lecture. I just felt I'd take class more seriously that way, and that's exactly what I did.
I can't say anything bad about SFSU--I don't really know anyone who went there, and I didn't consider applying there. And I've never heard bad things about it. I just know that it's a good program. Whether it's better than Mills is in the eye of the beholder. Mills certainly has a great reputation for getting their students into the UCs (we get a disproportionate number of students into UCSF every year). I think it's probably better known outside of CA than SFSU, but who knows.
Jo Scullion is the best resource that Mills has to offer. She's on top of what it takes to get into medical school and I used to stop by her office almost daily just to chat and share with her my admissions progress, etc. You couldn't ask for a better pre-med advisor.
If money is a big issue than SFSU certainly makes more sense--Mills does come with a price tag. Personally I found Mills to be worth it, but that's a decision each individual has to make for themselves. I also liked the location of Mills a lot--it allowed me to live in Berkeley and so it was really easy to volunteer at the Berkeley Free Clinic, which is where I was the most involved.
While Mills does not have a summer session, many of us took summer courses at UC Berkeley over the summer (the favorite biology professor teachers biochemistry there), as well as other electives. It was a lot of fun taking classes there over the summer--UCB's setting and environment is so different than Mills.
Personally, I'd recommend visiting both Mills and SFSU and sitting in on some courses. The professors and students you work with are what really makes a program great, so I'd go with your gut and go wherever you feel you'd fit in and be the happiest. You're going to be working really hard (get all A's and A-'s--nothing less! Seriously!), so you want to enjoy lectures and enjoy the people you work with.
Unfortunately I don't know anything about Charles Drew other than it's in LA, which for me is a big negative
🙂 To each his/her own!