[mswen]

Big company. Large retailers have lots of data and the ability to act on your analytical insights. Fifty percent more money is significant and you should discount any promises or grants of equity from the start-up. Equity in start-ups is far from assured and will often be subject to dilution, vesting periods and other constraints even if the start-up succeeds. And, in a couple years when you are considering moving to another job for better money and more interesting problems being already located in a very large city means greater ease of connecting and finding that next position.