If you are an established business with a good history of transactions, you could go to a more standard merchant service and negotiate better rates as well. I have a non-profit client who got really rock bottom rates from First Data (I'm in no way affiliated). After 4 years of using them, we looked at switching them to Stripe/Braintree, so we got together with their in-house bookkeeper and calculated what their fees would have been if they used Stripe for the last year. It turned out that Stripe was more expensive by at least 0.5%.
But here's the tricky thing - traditional merchant services have different rates for different kinds of cards (debit vs credit, loyalty vs non-loyalty, etc) whereas Stripe/Braintree/Paypal normalizes it all to 2.9% (etc). So if you're selling large ticket items, you might end up with higher costs because folks tend to pay with loyalty cards to earn points for large ticket items (loyalty cards carry higher fees).
More pros and cons:
Stripe/Braintree has much more features for developers and integrators. So they are much more "value-add."
Depending on how you implement payments, Stripe/Braintree is generally easier to meet PCI compliance.
Hope this helps a bit.