Thanks to Joe and some lobbying on my behlf he has added a PayPal express payment option to the Membership Pro module. It works perfectly. We just installed it on the "Society of Freelance Professional Designers" [SOFPD] http://sofpd.org/
We will also be migrating several other membership websites over to MojoPortal since we can now offer both Authorize.net and PayPal Express. We will post the migrated sites URL's once we've finished migrating them over.
Kudos to Joe and the PayPal Express payment option. From what I understand this option will also appear in other MojoPortal modules.