[superuser2]

Simple is an entire bank/debit card. Square Cash, Venmo, etc can all be set up on your existing debit card. I certainly hope I don't have to switch banks to do mobile payments.

[blhack]

All of the other mobile payments things seem like they want to be your bank (but only sorta kinda sorta).

Simple is just that. A bank (or rather, a banking services provider. Us bancorp is the actual bank).

The tight integration with mobile payments, because of them also being a banking services provider, is absolutely flawless.

[gress]

I use Simple, and Square cash, and I have to say that Square Cash is far superior for sending money to friends.