I haven't been tracking GIMP development for quite a while and couldn't find the information online.
Does the current version of GIMP finally support non-destructive editing (adjustment layers)?
Is GIMP still too slow for photo retouching?
Does the current version of GIMP finally support non-destructive editing (adjustment layers)?
Is GIMP still too slow for photo retouching?
Layer effects are planned for Gimp 3.2. http://wiki.gimp.org/index.php/Roadmap
It will be achieved by integrating the GEGL library (http://www.gegl.org/) which enables the use of OpenCL acceleration (http://www.khronos.org/opencl/).
As for slowness, it depends on what kind of retouching you are doing. I'm retouching mobile graphics assets, which are small enough and I haven't seen any lags. I image that things are very different when working with high quality photos...