Stripe Alternatives

I have been looking for some payment processing / merchant service alternatives.

While I love the Stripe API like many others, we certainly do pay a high premium for it. The recent policy changes for older users like myself make the service much less palatable.

What other options are there besides the most popular Braintree/Paypal, Square, etc?

I'm researching in terms of:

* Low Cost (% and Per Transaction Flat Fee) * API quality * Possibility of commission/referral fee kickback * Trust / Reliability / Longevity

Am I missing anything? What would you recommend?