Vantaggi
Life as a grad student has its perks. There is really very little supervision of anything, which is a double edged sword, but it means as long as you keep your adviser happy, you can do anything you want. Work as much or as little as you want, pursue side gigs, career development. Benefits are good enough if you can get them (UCSHIP).
Svantaggi
Life as a grad student is really strange--I imagine most of this applies to any institution. But it is really like the wild west in terms of employment practices. People can get hired or fired for any reason or no reason at all. Advisers insult and bring their students to tears. There is no pay standard. In some departments, advisers decide not to pay for some months because they're not happy with your progress. It's just a very strange and volatile environment. As always, time to PhD graduation is far too long.