Antialias effect intensity

[Hackerman]

Of course I can apply gaussian blur in selections (fuzzy tool selection, then float selection so as not to include colours outside the selection in blurring and after that gaussian blur). Why not? But it would create much better borders if I did it without aa and applying aa afterwards. I really haven't found a program that has a good aa option. I already tried Adobe Photoshop and Illustrator. So I'll try Inkscape next. Are you aware of any program with good aa options (eg selecting algorithm, intensity etc)?