Okay, so Platypus may be a lot more billing solution than a simple domain registrar may need, but if you're going to get serious with thousands or hundreds of thousands of domain registrations, Platypus can handle the task.
Support is top notch, the best in the industry in fact.
Sure, it's a bit pricey. You get what you pay for. Ya thats like trying to kill an ant with and elephant gun. We are also looking for a renewal billing solution.