I'm curious, why not use Stripe? I have heard nothing but good about them, and since you are willing to use Pay-Pal, I am assuming you are willing to use other 3rd party processors.

If you have your own merchant account and have implemented the code by hand or through a library, you pay all sorts of fees, sign up fee, fraud chargeback fees, percentage of charge, statement fee, monthly fee, etc. Both Strip and Square offer simple integrations, simpler than Pay-Pal IMHO, and I assume they have the capacity to deal with fraud better.