Well, ... Venmo allows the payment to be funded from a credit card.   That used to be provided at par (no fee for the transfer from a card).  Now they charge 3% apparently  (though for new users, the first $500 of charges is free from any fees).

 - http://help.venmo.com/customer/portal/articles/429494-why-is-venmo-charging-credit-card-fees-

As far as competing with Dwolla, t here are no bitcoin exchanges or intermediaries that accept Venmo payments.  So Venmo is no more like Dwolla than PayPal, AlertPay, Square, or the multitude of competing services.