If it's probably about a coinflip or better, and the pot is decent-sized relative to the largest stack playing, I'll push. Depends on the flop action of course. My usual goals with this kind of hand are

1. to be the most aggressive player - first to fire that much money into the pot
2. to be fairly confident in my rough idea of the odds (so if i have 13 or more outs, I want to be comfortable that all those outs are clean).
3. hopefully, to win the pot without showdown (which ties back into #1).

I typically use this move to buy pots with an un-made hand. If they call then i have the outs to fall back on, but I'm happy if they fold, since my edge is so small. A lot of the EV in this hand comes from the fact that it allows you to be so aggressive on the flop, comfortably.