hey i'm in a similar situtaion!
I guess the best way to make your decision is to meet the people, especially recent graduates and also the people who have been working at each for several years now and just find how they feel about their organsiations.
Also think about yourself and try to find out if you are siuted to a certain 'culture' yourself.
It's true that we are faced with an extremely tough decision - all of the people that I have spoken to are extremely nice and friendly! there is no wrong choice :S