Pros
Having the Yale brand on your resume is a terrific life-long asset. Generally the staff are very helpful. While my day -to-day life often felt isolated, I enjoyed my experiences with various student groups, seminars, etc. Also, the Graduate Career Resource Center is incredible. They invite top consulting firms, host resume workshops, dissertation boot camps, and invite guest speakers from inside and outside academia so you know all your options when you graduate. It's entirely up to you to get out there and make the most of your time at Yale.
Cons
As a graduate researcher, my day-to-day life felt very isolating. My once large and thriving lab shrunk considerably in size as people graduated and funding dried up. I found that un-tenured professors are usually very stressed out and can overwork their students. On the flip side, tenured professors are way too laid back and don't move fast enough on publications, grant proposals, etc. Choose your mentor wisely, and be sure to change mentors early on if things look like they're not working out.