AEM version 2 has the best knock map-style functionality ive seen so far, VIPEC and LINK have an ok system it as do the new Haltech's and most MOTEC (once enabled) so its not really an issue if you want it as most decent ecu's support it.
The NISTUNE setup is pretty cool and very easy to setup on your basic std engine but like all knock systems becomes harder once the engine and car become more modified, clutch choice, engine clearances and lash type can all play havoc with the knock sensors which require recalibrating to the "new noise" introduced with such modifications.