Pros
Possibility of working on cutting-edge projects, hopefully related to your field of interest or experience. Opportunities to work without much supervision and above your pay grade with little serious blow-back for failures. On site fitness center, dry cleaning, etc. Some managers allow flex time.
Cons
Read what you sign at hire--the paperwork that prohibits a second job also discriminates against hobbies, and some managers will force employees to drop outside interests and volunteering. Expect mandatory unpaid overtime, more the higher you go and including nights and weekends without warning. Getting on projects, promotions, etc. depends a lot more on who above you likes you than on actual performance. Discrimination and occasional bullying still present, some groups have severe morale problems.