I think one of the big factors in going with Stripe over PP Payments Pro was the strong technical side that Stripe offers.
I think one of the big factors in going with Stripe over PP Payments Pro was the strong technical side that Stripe offers.
I do not know if you (or anyone) would count them as a "traditional merchant account provider", however (or if they are really a "merchant account provider" at all; I will be honest and say I'm still behind on some of these terms).
(Also, for completeness: Amazon Flexible Payments, in a similar boat to PayPal and thereby falling under the same "already need" reason you list, also has good mechanisms for automatic chargeback reconciliation and reporting.)
I am bias since I work at Litle & Co. My team implemented the chargeback upload API years back, it's great to see it catching on.
Litle has some neat features including a JavaScript API for tokenization that we call Pay Page.
I won't go on self promoting, however I can answer questions if you have them. I follow hacker news because of my personal interest in software development.