One of the defining pieces of Jinteki ICE, the reason it receives a high impact is because of one reason. As a Sentry, it was powerful enough to severely set the runner back if it was facechecked, (run while it is unrezzed and encounter it with no breakers but ones face) and that meant that many runners would seek out their killer before beginning a run on Jinteki.
While Neural Katana has fallen out of favor for more taxing ICE like the above two, or for including more ETR ICE, it has a place as a special memory, and only one other piece of Jinteki ICE can do that much damage with a single subroutine.Cortex Lock is very similar, and possibly even better early game. Katana always fell off when the Killer was found, not even being much of a tax. Cortex Lock falls off even faster even without a Killer, but can be potentially more damage. So while not a straight 'better' card, Neural Katana's situational usefulness may be better achieved with Cortex Lock
(Written during the meta of Breaker Bay, part of the SanSan Cycle. For more reviews like it, visit wyldside.blogspot.com)