A lot of people like plain edge for one specific reason... as a user, you will need to resharpen the blade. And with a plain edge, you can do that yourself easier than with serrations.
People say that a sharp plain edge can do the same job as a serrated blade. I think serrations take the edge (hah, pun alert) when the plain edge blade starts to become dull.
And to be perfectly honest, you can't go wrong with either decision. Those zero tolerance knives are built like a tank.
Keep in mind that the 0300's are HUGGGGE and I cannot close it with one hand. The 0350's are more my size and are quicker to open since it is smaller but still robust.
I did a review on the ZT 0300's at http://www.youtube.com/watch?v=OXPhkfYskbY
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