Not bad theoretically but what if you had to use the shiv and had to justify yourself in court or were caught carrying it by a LEO. You would be in deep shit, a shiv is an improvised offensive weapon, period. The look, name, style, color, and everything else about a knife's asthetics says alot about what it is meant for. A sharp piece of sheet metal wrapped with tape or string is the weapon of an aggressor and a criminal, not an innocent. But, as per your OP I would choose a small fixed blade, mainly a LaGriffe, kabar TDI, meyerco wharning or claw knife, ecos kiradaschi would all be pretty good