A few things that seem to distinguish this program:
- use of pdf as a native format, not seen outside of Illustrator
- ability to shear a bitmap graphic! you can easily generate 3D cutaways from views of orthogonal planes. Just shear them appropriatly and paste together. Incredible!
- Simplicity! No need for a steep learning curve before getting useful things done.
- If all you need are bitmaps for Powerpoint, you needn't register. You can do screen captures...