The term "h4xx0r" can be used in both a positive and negative way. Typically, calling someone a h4xx0r is in the negative sort. But some h4xx0rs take pride in being what they are, just like nerds.
H4xx0r, is basically a computer-experienced person's/gamer's way of calling someone a hacker.
If h4xx0r is spelt with one or two big X's, that is the final form of the word and the highest degree.
h4xx0r, h4xX0r, h4XX0r.