Pros
Medidata really is the coolest company I've worked for so far! They fly you to New York to be inducted, and the company offer really cool perks and benefits - notably expenses paid trip to NY, gym subsidiary, discount stock purchase scheme, free private travel insurance (and subsidised medical and dental if interested), and free breakfast every first Monday of the month, as well as food for holidays, to name a few. Everyone is really friendly and will always give you the time of day for any questions you may. It is a really nice working environment.
Cons
If you do not work in the US, a large part of your team may be there and therefore the time difference can be the tiniest bit inconvenient but not a big issue. Also processes can change quickly and often, so not many are documented.