How do you like the Code 4? I really like mine, but rarely carry it. When I would need a blade that big, it's for cutting food on the fly, and then the thumb stud is in the way, as it is so far up the blade. Another thing is that the blade is 3-9/16", so if you were caught and they measured it, you might be in trouble. On the other hand, it is quite thin in the pocket, and the clip is short, so muggles don't know how much blade you're carrying. Just be careful the company you break it out in front of.
How's the Sebenza? Worth the centi-bucks? They seem like a rip-off to me. Diminishing returns, like with fancy cars or guns. Nicer? Sure, but not proportionate to the increased price. I'd be glad to be wrong.
I know this is the Cold Steel forum, but the previous poster was right about Spyderco dominating the <4" market. I have a few and my current favorite is the (affordable) Polestar. It's $70, has a 3.5" blade and all of it is edge. With the Spydiehole instead of a stud (like all Cold Steels seem to have), I can through-cut stuff with it. Only problem is that for $70, BD1 is pretty cheap steel. Cold Steel gives better steel for the buck. (S35VN in the Code 4, for example)