Recs.
Updated
SpecsUpdate
Pros
Pro Beginner-friendly
Gimp has less features than programs like Photoshop, but for a beginner, or someone not needing complicated options, Gimp is the perfect choice. It allows you to quickly do basic photo manipulation so you can easily get the product you need without having to worry about complicated features getting in the way.
Cons
Con Limited color profile support
Gimp currently only supports sRGB. CMYK or even other wider gamut RGB color profiles are not supported yet. This severely limits Gimp uses as a tool for many commercial level projects, projects that require color high consistency between different types of media assets, and any production pipeline which works with physical media.
That said, this is an issue they are working on with GEGL and babl, which ultimately could bring these features not only to gimp but to many other opensource applications as well.
Con No non-distructive editing
Gimp currently lacks non-destructive editing, This severely limits Gimp uses as a tool for many commercial level projects. To some extent on low level projects this isn't an issue because of Gimps use of their history feature but its not the same as actually providing proper features with non-destructive editing capabilities.
That said, this is an issue they are working on with GEGL, which ultimately could bring non-destructive editing capabilities not only to Gimp but to many other opensource applications as well.
Con Less features than other programs
Being a free program, it shouldn't be surprising that it has limited features. For those needing more advanced features for something more professional, GIMP just isn't for you.