How does an IPN integration take days? It's just a webhook, which most every 3rd party processor has copied. You take a POST and send it back to validate it. It can't be more than a few dozen lines of code at most, and there is a decade of libraries available for every possible language, framework and cart that turn it into a single function call.

I've never found anything easier to integrate, and I've done PP Pro, Authnet SIM, Authnet AIM, Authnet CIM, Quantum Gateway, Google, Amazon, Recurly, Spreedly, Spreedly Core...

I'm not the OP, but PayPal is not only cheaper (that .7% adds up fast), but without it I'd lose more than 10% of my customer base, and that's very significant money. Credit cards with AVS are just not readily available, or socially common, everywhere in the world. Stripe is a way to accept credit cards. PayPal is a way to accept payments from 190 countries. That's not the same thing.