My favorite thing about CSU Northridge is that they are such a nurturing school. There are many many resources to help students succeed. There are a lot of different places where you can get free tutoring for whatever subjects you are struggling with.
If I could change anything about CSUN, its that I would make more class sections. There are many students and limited class seats, so you have to really plan in advance what classes you'll be taking and contact professors to try to make sure you get permission numbers. I heard that next year, professors won't be able to so if you can't register for the class you need on your registration date, then there's nothing you can do. A lot of students struggle with this, and have their time in college extended because they can't get the classes they need. However, this should not be a complete turn off. Students who are involved in certain activities like honors programs, or peer education programs like JADE and Blues Project, get early registration dates so they can get the classes they need. So if you go to CSUN, be sure to get involved so you don't have to worry about not getting your classes!
CSUN is a pretty large school. However, once you get to the upper division classes, class size is about 30 to 40 students. While it's not the itty bitty size you can get from private universities, it's small enough that you can get to know your professors if you make an effort to. When I tell people I go to CSU Northridge, they usually say something like "Oh hey, that's a pretty good school. I heard they have an excellent business school". Overall, there isn't much school spirit because its a commuter school and sports aren't very big. It's not the school for you if you want a traditional university experience with lots of school spirit.
The biggest controversy on campus is the budget and how the CSU chancellors are handling things. There are lots of theories floating around that they are mismanaging the funding. I don't know if that's true, but I have yet to be presented with any evidence that that is the case. The state of California has a very bad budget crisis, and for some reason they feel like the easiest way to save money is to cut the CSU's budget and raise tuition. Every semester I've been at CSU there's always a protest at some point about the CSU being greedy and how everyone has a right to education. I don't think the CSU is greedy, they just don't have that much money. As for a right to education, the students with the most need are still given grants and don't have to pay tuition. For everyone else, in my opinion, CSUN is still an excellent value, as its still half the price of a UC and less than a quarter of the price of the average private university.