... I seem to recall an old Indian Joke about Two Dawgs ....
Dear TD,
I can only really answer your question from my own perspective and experience.
Generally higher-end plug-in and filter active type people are fairly good or prolific artists and computer artists ... thus their preference is for pretty powerful drawing-painting software.
One of the problems that has been around since the late 1980's (first fixed by a IMSI program - Page-Perfect - in 1988) was that the graphics painting/artist programs were program-biased/designed, rather than designed by artists/painters ... so they had lots of capacity that was not practically possible to apply, or bloody hard to do.
Corel 3~5 were OK, but then did the same mistake and became a genuine artist's nightmare.
IMSI went on to make Photo-Impact but lost the lead when Paint Shop Pro 4 came out. Instead of getting better, they got gradually worse (harder and harder for artists to use), so people deserted the product (like Corel).
These days its a race bewteen Photo Shop (Adobe) and Paint Shop Pro (Jasc).
Personally I think Jasc leads and will always lead, because the program has a basic priority to place the raw artist tools first ... and all the extras second.
Example (though line-wise & freehand shading, none are as good as the 1988 IMSI offering) - try finding an easy/direct way to draw/all lines in Photo Shop 7x or Corel 11x. Should take a few hours. PSP is not perfect, but you can find the line tools in a couple of seconds and they're fairly artistic-user friendly.
GIMP2.0
Now Gimp was designed first as an effects and manipluation tool - albe it one of the most comprehensive around. It is extremely good and well written in programming terms, plus has a couple of excellent exclusive features ... but the layout is programer-biased and pretty difficult to master if your priority is an Artistic-creative bias.
As it is not very originating artist user-friendly (way it is laid-out, not what it can do), most artists will do their artwork on something-else first ... in preference. This makes Gimp lose its advantage (effects and features), because you have to save and exit. Then re-open the file in Gimp to apply the effect.
Although most Gimp effects are better than the basic effects in other software, the genuine artists/creative graphic people are very good with what they have, are used-to, and have added ... thanks to people like Harald and company (those who write/make/design plug-ins and filters).
Gimp2.0 is good; however with the various plug-ins and filters I have collected over the years (many available from Harald's links ... for free), it is not in the same league as either Photo Shop 7.01 or Paint Shop Pro 7.04.
If only wishing to modify existing images, it is about the best you can get (free or paid-for software); however in my experience most people in Harald's 200,000+ rabid readership are long-time creative applied artists ... who usually originate artwork, then modify what they've done.
I hope this kind-of make sense. I have Gimp2.0, Corel 11, PSP7.04, PS7.01, and (on this system) about thirty other graphics suites.
95% of my original work is done by PSP7.04. 35% of my modification work is done with Photo Shop 7.01 (including checking/writing/modifying plug-ins, etc).
Gimp will get better. Keep in mind the others are a decade ahead.
Cheers,
Rick.
rix@multiline.com.au