I use Inkscape for nearly all visual projects, but do have GIMP for the odd task. Many folks use and like Krita, so I took a look at it. Even though recently I've seen how to do 2d animation in Blender, it seems that in Krita it is a bit easier. And so I've decided to add this tool to my toolchain.
Krita niche
According to the Krita roadmap it's niche is creating digital images from scratch. This means that focus on editing photos is left to GIMP, and also that the text tool has been somewhat neglected (though it is being reworked). Clearly when comparing Krita to GIMP (its' foremost rival), they both have bright spots and are clearly useful together as well.
- Brushes, including resource management of brushes and textures
- Some vector integration
- 2d animation, including multiple layers and audio
- Layers, selection, transform
- Full color support, and GPU utilization
Open source design tools
- Inkscape (Vector graphics, output to PNG and PDF)
- Krita (digital drawing, 2d animation, mainly bitmap but some vector tools)
- GThumb (for simple image resizing, format conversion, image management)
- Blender (very complex tool, 3d and 2d creation, animation, also video editing NLE)
- Raw Therapee (Image collection management, batch editing, import RAW files)
- GIMP (Photo editing, photo and text)
- Shotcut (video editing NLE)
While it is true these are quite a few tools, for certain tasks, some of the tools are vastly superior. For me, I don't deal with RAW images and so I can use Gthumb instead of or without resorting to Raw Therapee. I can also use a combination of Inkscape and either GIMP or Krita. For 2d animation and digital drawing and painting, Krita has an edge over GIMP, to some extent.