Penn State features a wide range of professors and class types. Most teachers are well trained in their field, but there are always exceptions to the rule. Just like most schools, graduate and international students serve as teaching assistants. Some can be easier to work with than others. It becomes pretty easy to learn which professors are student-friendly and which ones to avoid. Upperclassmen and Web sites like RateMyProfessors.com are good sources to guide you. The bottom line is that your effort will usually dictate your grade: If you put in the work, your grade will reflect it.
Class size also varies widely. It’s easy to get lost in the large auditorium classes, but these are unavoidable when you’re working on general requirements. As you progress in a major, though, you’ll find that classes become smaller, more discussion-oriented, and more personal. Penn State has a lot to offer academically, and this is especially true if you’re motivated to learn.