I’d consider myself, formerly, to have been a reasonably skilled user of Photoshop, up to Version 7 (so many features got added after version 7, and name changes)… I used Photoshop from about Version 3.x on Macs and Windows 3.1…
I’ve never found anything that I could do in Photoshop 7.x, that I wasn’t able to do in GIMP… having said that, I’m no photographer or anything…
As for Vector Graphics, same goes for Inkscape, I never got my head around Adobe Illustrator, but I’d consider myself a “power user” of Corel Draw - and there’s only one feature that Corel has, that Inkscape doesn’t and that’s multiple page documents… In fact, I often find myself cropping photos in Inkscape, Vs GIMP, using the “vector” drawing tool (bezier curves), create a new object, fine tune it till it’s the same shape as the part of the bitmap you want to crop, then do some boolean on the bitmap, using your vector shape… no good? Undo and tweak the vector shape till its perfect…
I’d love to see multiple page documents in Inkscape… Tried “SK1” which is another “open source” vector editor, but it’s flakey, and I don’t even know if it’s being maintained…
For my money, Inkscape feels every bit as professional as Corel Draw…
And for common “tasks” with images or photos, what can be automated or scripted, I do using old faithful “imagemagick” (most commonly accessed using the “convert” or “mogrify” tools, and just about every website in the 1990’s used imagemagick through CGI-BIN)…