Avantages
Genentech is laid back and a fun place to work. People work hard, but don't live stressful lives. As a co-op, I was given meaningful projects and even got the chance to get my name of a paper. the Genenbuses made it easy to live in the city and the free muni passes made it easy/free to use public transportation. The lunches are really good and affordable. It was nice to never have to worry about packing a lunch.
Inconvénients
There isn't too much that I can say about my experience that was bad. There wasn't enough space for the co-ops/interns in my department, so some had to make their lab their desk. I was also there when Roche took over, so I only saw the beginnings of what was to come, change-wise. I've heard that they've made an effort to preserve the culture.