For SAAS type subscriptions, I was pretty happy with Spreedly http://spreedly.com/ http://spreedly.com/ One thing that is pretty cool is they let you be merch

For SAAS type subscriptions, I was pretty happy with Spreedly http://spreedly.com/ http://spreedly.com/ One thing that is pretty cool is they let you be merchant account agnostic (all CC's are stored in their own PCI compliant vault). So if Authorize.net drops you or is being stupid, you can setup a different merchant account and the entire thing is transparent from your customer's perspective.