Vantaggi
Good environment, vibrant teams, good leadership (though it depends on teams). You will have ample of learning opportunities in terms of process, leadership skills etc. Outing, transport, subsidized food are some of the perks you get working for amazon. It's also a very fast paced environment, if you don't cope up you will be shown the door one way or the other (It's what defines amazon, "work hard, have fun, make history")!.
Svantaggi
The pay is very low for freshers! If ever you get into non technical profiles, forget about decent salary!. The big brand that amazon is will be the only thing to make you stay much longer. In some teams there is no concept called growth, I know some guys who are stuck there in the same entry level positions for over 5 years or so with the same old stingy package!