Braintree Payment Gateway
I recommend adding Braintree Gateway that uses their Braintree vault. There is now no third party that has a braintree module that utilises the vault.
Braintree has quick pay out time usually in 2 days and it's fees are low!
Braintree is a division of PayPal and will be a great addition to WHMCS!
VOTE VOTE VOTE (Please make it :))