RawTherapee is a RAW photo post-production tool designed for professional and beginner photographers. With its help, you can manipulate and convert your digital pictures with no quality loss or waste of your time in the process.
The program is compatible with many file formats, gives you access to a wide range of editing options, and provides you with quality output files. You can use the built-in browsing tool to preview the digital images from your photo collection, rate your favorite pictures, and batch edit the RAW files.
The only thing that bothers me about this utility is that its interface is too overwhelming as many options, tools, and buttons are being displayed. To be more exact, it took me a while to find the tools or buttons I needed from the "crowded" main window.
Still, if you're familiar with this type of image manipulation tools (most advanced image editors look like this), you will probably need only a couple of moments to learn how the program works and where to find the options you need.
To conclude, RawTherapee is a feature-rich and effective editing and converting solution for RAW files. And since it comes without a price, I can't find any reasons why you shouldn't give it a try.