My problem with gimp is that I've never really used Photoshop (I may have back in it's very early versions, but I don't think so). I mostly just use something like Ms paint to take and crop screenshots or photos. Jumping into gimp (and presumably PS as well) is going to confuse people trying to do that.
I still don't know how to use gimp just because I never need all that functionality and don't have time to learn. Maybe someday.