Best online places to find remote developers?

We are just about to embark on hiring another Ruby/Javascript developer to join our team to cope with our development demands and growth.

Curious as to which remote job boards have worked the best for others when trying to find developers?

We've tried the usual generic job boards, and some remote work ones in the past, but the quality of applicants was quite widespread.

We are looking for a job board which is (a) solely focused on experienced developers and (b) is focused on remote only work.

We are more than happy to pay for listings on boards that can give us high quality applicants. Where have other IndieHackers found their developers from?