Avantages
I attended MIT as a grad student and worked there for several months afterwards as a postdoc. I found my department to be very supportive and close knit, and the students, faculty, and admins were smart, friendly and kind. I also had some great interactions with other employees of the institute. For example, an additional water fountain was really needed in the student center to accommodate student events, and when I contacted facilities about it, they took care of it right away, and checked in with me throughout the process. I was so impressed!
Inconvénients
After transitioning from being a student to being an employee, I ran into a couple of challenges. The first is that, while students are easily able to get their chosen name (as opposed to legal name) on their MIT IDs, the process is prohibitively difficult for employees, which can make things difficult for trans and nonbinary employees in particular. I also had an issue with my pay not being handled properly that had a large financial impact while it was ongoing, and my initial point of contact for that in payroll was very harsh and unempathetic. Overall, I was left with the impression that the institute provides a more supportive environment for students than for employees.