Punchneedle embroidery

Does anybody here have any experience with using a punchneedle to do embroidery? I’m considering purchasing this model:

http://www.amazon.com/Clover-embroidery-stitching-tool-punch-needle/dp/B001W2IAY8

but I’m hesitant to buy another tool that I may not like. I want to know how the results can be. It looks kinda cheap on the package, but that may be due to the simplistic designs they use as illustrations. How sturdy are the backstitches?
Additionally, I’m unclear on how these tools work; is it only worked from the top, or does it get passed underneath? :confused:

Dopers, can anyone enlighten me?