Here's my take. I would get the 720 personally.
for the 720:
the display is superior (higher quality, sharper, but smaller at 4.3")
Qi wireless charging option
much much better camera, front facing too
for the 625:
larger (4.7") display
LTE (4G)
swappable back covers (different colors!)
slightly faster under the hood
worth noting both have some of the better battery lives around, same battery size.