I have been considering FastSpring (http://www.fastspring.com), which has recently added subscription payments as a feature. I'm interested to hear about anyones experiences with them.
It is a bundled payment gateway+merchant. You don't have to get PCI compliant and you don't need a merchant account (no min transaction volumes, fight chargebacks for you etc).
The down side is they only offer hosted payment pages and not suitable for everything... You need a finite set of goods/services you want to sell (eg monthly plans). You can't automate the process if you're building an online store where your customers can upload items for sale (eg AppStore).
SaaSy is a service from FastSpring, just to clarify. To see what people say about FastSpring, try searching online or you can view what they're saying here:
http://www.fastspring.com/clients.php
Some samples:
"I'm going to come out and say it: FastSpring is awesome. I haven't experienced customer service this good in my life. Every query I've had, from stupid questions to difficult questions to bug reports has been dealt with brilliantly."
- Daniel Kennett, kennetnet
“FastSpring is definitely the best company I have ever interacted with (note: the best company ever, not just related to e-commerce).”
- Ruman Stankov, Triland Inc.