Ask HN: Do developers prefer a free trial or freemium?

I've launched an MVP of a service that's targeted at iOS developers (www.pushlayer.com, if you'd like to check it out). I'd next like to experiment with the signup process to make it as frictionless as possible.

I'm thinking of either: (a) not asking for a credit card on signup but sticking with the existing 30-day free trial, or (b) making the service "freemium" in that a user can signup without a credit card and use a restricted set of features indefinitely.

If you're a developer, which do you prefer?