I never cared for Gimp, I found their UI unusable - for me - and they don't work with RAW, or didn't at the time. I won't edit JPEG if I Can avoid it because of lossy compression, you lose detail every time you save it. Of course, you can save as TIFF or some other lossless format and then export to JPEG when you're done, you just have to develop your workflow around that.