RawTherapee is described as 'Powerful cross-platform raw photo processing software offering advanced user control over demosaicing and development. Supports HDR DNGs and image formats' and is a very popular raw photo editors in the photos & graphics category. There are more than 50 alternatives to RawTherapee for a variety of platforms, including Windows, Mac, Linux, iPhone and iPad apps. The best RawTherapee alternative is Affinity, which is free. Other great apps like RawTherapee are RapidRAW, darktable, digiKam and Adobe Lightroom.
Unlike RawTherapee, darktable garbaging your drive with xmp files for every single photo you have in the library. RawTherapee only does it for edited files. And you can't cancel it. Once started it will do it even if you close the app. RawTherapee also has more classic understandable interface, though doesn't have light UI.