Pros
The university is huge and well-ranked, and consequently well-funded and prestigious. The campus is beautiful and depending on field, you will likely have access to tons of networking and collaborations. GSR's and TA's are unionized, which greatly improve the ability for grad students to advocate for better conditions.
Cons
Your experience depends 99% on your graduate advisor/PI. They may or may not have any funding for you, and often lie or mislead students about their funding stability. The advisor-student relationship is EXTREMELY influential on every aspect of your experience, so if you have a bad advisor you will have a terrible time. There is often little structural support for workplace abuse and harassment. Advisors are very rarely hired based on their ability to be managers, and it shows. Especially among junior professors.