I guess the difference would be how many games you can fit in each. I use Nintendont with USB sticks (Some Toshiba usbs) and it works wonders. Not even a problem (Except those games that doesn't want to be shrunk). Just format it with a cluster of 32kb and you're good to go.
In a 16GB usb you can fit at least 10 games if not shrunk. If they are, it depends on which games.
But, why use Dios Mios? Nintendont seems to be better in every way possible to me. You don't even have to install anything so you still can play retail games. If you have, of course.