Ask HN: Recurring Billing Solutions

I'm researching recurring billing solutions for my web app. So far I have taken a look at:

http://www.chargify.com

http://www.braintreepaymentsolutions.com

http://www.payfacade.com

http://www.cheddargetter.com

http://www.spreedly.com

...and obviously Pay Pal. Any recommendations here? I am looking for something that is affordable and easy to use from a development perspective. There have been threads like this in the past but I wondered if anything new has come out since then.