I'm kind of bummed to see him doing good things with a product I consider a core part of the services I use and then leave to join a product I don't much care for.

What's great about Paypal is that it's good for both business and personal. Facebook is horrible for making that separation. I couldn't see myself using Facebook over Paypal. Though most important is the adoption. If it's easy and everyone is using it, then I suppose that could change my mind.

Good luck to all involved.