The resulting texture is very different to the source one. I looked at this site and there aren't many good inspirational images in their gallery. Based on this result, I certainly wouldn't recommend this software, MaPZone is better - and free, but is rather more complicated. Redfield's seamless workshop
(also free) can produce decent results, but if you want to create good seamless textures, you need to spend a little time in Photoshop or another image editor, or use a more powerful tool.
The importance of this can't be overstated because you can never have a decent render without good textures. However if you start with excellent texture maps,you can improve an otherwise pretty crappy render.