As a sender..

With lightning it's immediate within seconds. You only need a lightning address or invoice.

With Venmo you need to know the receivers name or email and phone or other kyc info to send the first time. By default details of the transaction are public to a social graph

As a receiver..

With lightning you can immediately spend it. Or save it.

With Venmo, the credits sit in the account until transferred to another proprietary Venmo user, or a lengthy withdraw process to a traditional bank for spending