Originally posted by bertwert GIMP and Darktable are different tools for different jobs.
GIMP is more or less an open source equivalent of Photoshop, and Darktable more or less an open source equivalent of Lightroom.
I fully agree.
Put another way - GIMP is more of a general purpose tool that can be used for editing photos, whilst Darktable is specifically made for the purpose of editing photos.
I have used GIMP to edit out distracting elements, but for manipulating contrast, exposure, correcting lens errors, noise reduction etc. you can't beat Darktable.