In my opinion, Cold Steel can make some decent products for the price, but the way they advertise is sometimes ridiculous. They sometimes try to market pure combat knives for general use and self defense...however, the size and weight of a large knife for combat is usually not a big issue, but for someone wearing normal clothes, the practicality can be challenged.
A larger fixed blade is sometimes not practical for carry, IMO. It may not be legal, it is bulky, heavy, and not always easy to deploy. A small specialized micro-sized fixed blade or specialized folder may be better candidates to fill the gap. In my opinion, this is a gap that is ideally filled where you strike & run away like the wind, or at least put enough distance between yourself and the bad guy where you can then use a firearm or other method with less inherent risk that can come from being in such close proximity. However, there is a ton of different opinions on this topic!!!
I find the waved opening system, designed by Emerson and legally copied by Spyderco and others, to have the advantage in a stress situation in that the moment the knife leaves your pocket it has already locked open...with most other automatic and manual opening mechanisms, you have an additional step to take to open the knife, and pushing a small button, switch, or thumbstud may become a difficult thing to do knowing you are feet away from someone who is going to try to kill you.
There are numerous options for these specialized knives. A tactical pen, which can be used as an impact weapon, may also have benefit.
Here are some examples...among neck knives, the Ka-Bar Last Ditch is not only effective, but only costs 10-20 bucks. First-hand accounts of usage speak to its effectiveness.