If you want to carry it day to day choose the in production G-10, if you want one to look at, collection purposes choose the Carbon fiber, or the older alum. handle. :)
Zens pretty much got it! PE only comes in the older models.
Let your opponent graze your skin and you smash into his flesh;
Let him smash into your flesh and you fracture his bones;
Let him fracture your bones and you take his life!
-Bruce Lee-
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I carried one for a few days, but found it too large for the way I carried it. The bugger bit me not 2 minutes after unpacking the thing ! I now carry a Meerkat, which is great for general cutting. I have NO plans to use it for self defence !
I prefer the G-10 to the aluminum... The CF can be a bit pricey for a carry knife, but it is one of the more interesting CF peices Spyderco has made IMHO.
I found the civ too big for edc. Dodo is much more useful. The short blade and excellent handle makes for very powerful slashes. A better all around blade.