[JayNeely]

Spreedly.com's still going strong; used them when they were first getting started in 2007. They're still top in my book because they've done the best job of integrating with numerous payment gateways, and their Stripe-competitor, SpreedlyCore, is looking promising.

http://spreedly.com/ https://spreedlycore.com/

It's also nice that their pricing is all flat-fee per-transaction.