I don't know about now, but I've encountered significant issues with it every time I've attempted to use it in the last three years. To be fair, I was attempting to use it through wrappers - I had a particularly bad run trying to get around issues with both rmagick and minimagick in ruby, and later on a different project with wand in python. Though, with wand, the issues I encountered there were mostly with getting a buildpack working for it on Heroku.

Regardless, whether it's my incompetence or imagemagick itself, I don't have very good associations with the library.

GraphicsMagick fixed all the memory and CPU problems that ImageMagick was giving us in a large wiki farm production environment. That alone is a reason to switch to it.

Imagemagick does support some more advanced features such as deep colors, perceptually uniform color spaces (cielab) which graphicsmagick does not.

As I understand it some of the IM features are important for scientific image processing, HDRI or deep processing pipelines where rounding errors could accumulate.