There are quite a few differences.
The techniques used to create are the same between both versions. However, the full version allows:
<UL TYPE=SQUARE><LI>Canvas size up to 4096x4096
<LI>Import and export OBJ and DXF 3D formats
<LI>Save models
<LI>Import and save textures
<LI>Record ZScripts
<LI>Import Alphas
<LI>Save Materials
<LI>Use more than 4 layers
<LI>Use more lights
[/list]
There are probably a few more differences, but those are the ones that I can think of off the top of my head.