It is a great opportunity to immediately get given responsibility and learn a lot in a short time for graduates. Great for a hard-working, ambitious people.
Cons
Long hours, only good for people who are interested in their work otherwise it's hard.
Startup vibes, interaction with many cool projects in the industry, chance to meet potential co-founders and other helpful people for your network, interfacing with investors and other potential future employers
Cons
Not necessarily a con but hard work is expected, won't get by slacking