Classes are large at Berkeley, and most professors will not know your name -- it's nothing personal -- but they are very good professors able to handle such lectures, and so discussion does not suffer for the number of students there. I don't think I need to proclaim the greatness of Berkeley's academics here, but it's worth noting that the math and sciences are notoriously difficult and rigorous, and the humanities less so. In my own defense, it appears that the Philosophy department has the lowest average GPA of all the humanities-- though, upon further reflection, it's possible that this indicates that we're dumber rather than that the classes are harder and methodology more critical. Seriously though, I would certainly say I've had an easier time in the classes in my other major, Religious Studies, but I rely heavily on my own passion for the material so I am reluctant to set standards for others. Needless to say, Berkeley is tough, but it's worth it. Or so says one who never had to take an o-chem midterm.
To understand Berkeley's academics, understand simply that there are many people, that they are smart, and that they all must struggle -- even the best -- with on some level being nobodies. With the right attitude, it is a healthy struggle, and one that I personally was looking for-- no one will tell you that you are special unless you truly go above and beyond because it is assumed you are already special enough for getting here, and anyway, what was your name again? One of the positive developments of this scenario is that, in my experience, students very rarely seriously compete with one another; even in the classes where the grade is curved, everyone just wants to do their best, and people always cooperate. And even if the professors are so barraged by exceptional people that they have a hard time picking you out, they are always willing to talk with you because the vast majority of them truly love teaching-- even if they don't have a Nobel Prize yet.
The lack of core classes also provides an interesting element, such that all majors end up taking interesting classes full of people who have not been forced to attend; you may miss out on reading some of the classics, and you may find yourself picking certain classes simply because you know they'll be less stressful than other classes that will fulfill that requirement, but you'll be thrown into unusual situations as a result-- which as I have said is for me the theme of UC Berkeley. Applying my philosophy-trained mindset to my Environmental Biology class sophomore year resulted in some very interesting interactions that I will never forget.
People at Berkeley are more career oriented than they have been before, I think, due to the changing student climate, but as I have emphasized, anyone can find their niche, and the professors teach their classes out of passion, passion that you as a student are encouraged to share for its own sake.