The big argument to wait is of course that you save money, as San Francisco and New York City can bleed you dry pretty quickly. You can also get an employer to fit the bill for some of your move. Plus, with the Internet, you have countless opportunities to job seek from your current location anyway.
On the flip side, when you just go ahead and move, it means you can start networking in person right away. Moving now also accounts for instances of spontaneity, where your dream job is open only momentarily and you need to act quickly. And finally, moving now creates an extreme amount of urgency to succeed. It is sink or swim! You can read Hopkinson’s full article here: http://www.salary.com/move-before-or-after-new-job/