Both are currently for the U.S. only and both have phone apps. Only your bank account are supported for funding, so sellers will be happy with this if they are looking to avoid credit card chargebacks. Dwolla also got this GPS feature with their app where you can track locally who accepts payment through it. Both these software appear to have good API support too. Venmo is currently free but might charge in the future, and Dwolla charges 25 cents for receiving money. Hopefully both these services will also go international to cover more ground and to challenge Paypal.
Venmo and Dwolla are good but they are not as famous as Paypal as Paypal is used by all over the world people for online business,services,buying or selling
Well, like the old cliche, "Rome wasn't built in a day". Hopefully these 2 services can get more popular to be on the level with Paypal since Paypal is already mostly what people only know and what a quite number of people want to change from using