summer or grad? and when did blackrock offer come out 

ofc jp morgan la, learn a lot more than sales and more reputable, sales has a narrow exit path despite front office and long term wise sales isnt the best career

totally disagree, once you in middle office hard to get out, unless you sole purpose is to work in ibank , plus JPM corporate analyst is middle and back office rotation.

blackrock on the other hand is the largest AM firm, you will have all the exit opportunities in Wealth Man / institutional Sales World.