HacX itself was generally unsucessful; by the time it was released, the superior Quake engine that had just come out made the DOOM engine pale in comparison. Public interest for DOOM and games derived from it was, effectively, dead; even though HacX was a decent TC, it arrived on the market too late to become a success.
It was originally priced at $15 and was useful, at least, for stealing sprites and other graphics to create your own TC/PC (partial conversion).
There was also a HacX 2 in the works, but it failed due to a number of problems.
HacX is now being distributed for free on its website. The original site, maintained by Nostromo, may or may not function. Ownership of the site was transferred to Bob Larkin, creator and maintainer of the Doom Wad Station, in March of 2003.