One of the best suites of tools for working with RAW image files regardless of price, and with its very active and cooperative developers community it just gets better and better. It is not intended to be an "editor" but rather a "finisher" of images. This requires a very clear concept of what one wants out of an image — not some vague sense of "vibrant" or "sharper" — which can be challenging at first, especially for one accustomed to dumbed-down editors that offer automated quick fixes. Yet the precision and versatility of this collection of software is well worth the effort, and helps to encourage better exposures to start with.
Be aware that the core development occurs under Linux, the OS X version is a port maintained by a separate group of volunteers, and there often is a lag between versions. Also, new hardware support can be delayed depending on who is available to code and review it, but when that support does get committed, it is typically better than the manufacturers' own support.