Tools, especially Bezier curve tool, are much easier to learn to control than the identical tools in Illustrator. Both Adobe Illustrator and Inkscape are installed on my computer, but I invariably open Inkscape. I almost can't remember the last time I opted for Illustrator instead.
Layers make it easy to organize my illustrations for editing later.
Preferences let me set InkScape to recognize that I have a pressure-sensitive tablet.
Slow to open, but once the program is open, I don't have any problems with speed.
The program doesn't hold exact illustration sizes, The changes are miniscule and may be related to the number of pixels in the line stroke.
It would be really great if there was an option to keep the stroke width when resizing. I realize that in most instances, users would want the program to scale the stroke width when resizing, but for my purposes, I sometimes want the number of pixels in the stroke to be constant. Sewing pattern pieces need the same size border on all pieces, but if I decide to change the size of a pocket, for instance, I'll need to alter my stroke width.
If you are looking for vector image software, this is a great program. Even though I have Adobe Illustrator CS4 on my computer, I've been using Inkscape almost exclusively for a few years.
I'm a photographer just getting started with using my photographs to create fabric art patterns. I place my photograph on a layer and then create new layers for a line drawing of my photograph. These images are simplified compared to the detail visible in my photograph - reduced detail is a great benefit when using photographs in Hatch embroidery software and Electric Quilt software.