I'll break down my review of the university into two categories
UC Berkeley ranks among the top academic schools in the nation, especially when it comes to engineering, pre-med, and business. If you are majoring in one of these fields, prepare to be challanged. YOU WILL struggle to get A's, YOU WILL work hard, YOU WILL be frustrated at times. (especially if you are an EECS or Architecture major). Then again, you will learn a lot and earn a prestigious degress.
The other deparments are good. Being a big university, however, you really need to pic your classes carefully. Not doing so you may find yourself being tought by a GSI who can barely speak english, or a class that just isn't exciting enough to keep you awake during lecture.
No matter what your major, UCB is a great choice for academics.
I am only a freshman, so I haven't fully experienced everything the social life of cal has to offer. I am involved with the greek life here at cal, and I have to say it is a lot of fun. I can usually find a party every thur/fri/sat, and if not, there is usually something to do. Bored of berkeley? Hop on bart or a train and get into San Fransisco, where you can club or shop the night away. I love the social life cal offers, but I found that w/o greek life, social life would really be boring here. The greek system really opens up a lot of oppurtunities that I never new existed, both making these oppurtunities more accessible and less expensive.
If you have any questions about berkeley, I would be glad to answer them. My email address is jmars at uclink4.berkeley.edu (just replace the at with @, this is to avoid spam).