For me the nuclear serrations are a useful addition to the TTKZ .... they offer a number of advantages ....
Firstly if you are clearing brush and chopping down by the ground you can use the serrated side and it stops the knife edge from dulling or getting "dinked" near the point from contact with stones .... very handy if you are just using the Khukri as your main blade because then you can preserve the tip and edge for working on game preperation ....
I also find that chopping the blade into a log using the serrated side to anchor the knife so that I can run small game along the knife edge using it in a fixed position is a lot better than trying to hold a none serrated TTKZ down by the point using the flat spine to try to do such delicate work ...
Again, using the same technique of sinking the serrated edge into a stump I find that if I have chopped into a log with a view to spliting it and it is the first chop which goes deep and is difficult to get the knife out ... I invert it and sink the serrated edge into the stump and can then bash down on the log with either another log or even a rock without damaging the knife .... that usually gets the blade sunk right up to the spine and then you can take it out with the log firmly placed and turn it over to batton the blade through .... using a wooden baton on the serrations does no damage to the knife and a strong baton lasts for days before the serrations have cut through it .... weeks even .... and even then the baton just goes into the wood pile and I find another ....
The serrations are also great if using the Khukri as a machete to clear a way through head high foilage etc ... the serrated side catches and cuts small thin leafy branches much better than the sharpened knife side .... no matter how sharp the knife side is .... but you do need to keep the serrations sharp too ...
On fire prep the sparks you generate from a ferro rod using the serrated sharpened tips are way superior to anything you can generate with even the best of flat right angled spines .... and ofcourse this preserves your cutting edge as the only option to get good sparks if the spine were the normal rounded one on the TTKZ or the KZII is to use the edge. Unless ofcourse you carry a specific ferro rod strike with you .... but even then I get a better shower of sparks from the serrated edge than from the strikers supplied with most of my ferro rods .... the only comparable is when the striker is a proper piece of cut down hack saw blade ....
Another real benefit of the serrated spine is if you want to cleave a deer carcass down the sternum and split the spine .... it is ideal for this and spares the main blade any dulling or damage from the hard bone ....
Finally the weight and balance of the Nuclear KZ's is a lot lighter and faster than the others and for me that is perhaps it's best feature as the NTTKZ chops just as well as the others but is much better for extended periods of use .... easily able to be used as a machete if you need to .... so for me the Nuclear version of the Zilla is definately an advantage.
On a smaller blade though .... something in the 4 to 5 inch range where you may want to use a choked grip or work with your thumb along the spine for delicate cuts .... then naturally I would'nt go for this feature. All my smaller blades have either flat spines or may have a sharpened clip point such as on a Ratmandu ... but you don't need the full nuclear treatment on knives like this .... as it is better to have the ability to work using a flat spine .... especially if you want to hold the knife near the point for carving .... but on a larger blade such as the KZ it is a good advantage for me ....
Here are some pic's of what I mean ....
This one below shows anchoring the khukri in the stump using the serrated edge ....
A swift bang on the log and it easily split ....
And chopping wise if you chop around a log as seen below you can still baton the blade through in the centre to split the log if need be .... the serrations don't stop the knife being batonned at all ....
And the serrations are also handy for fire preperation if you just want to dig out a few wood chips onto a tarp to use as dry kindling ....
Gets a fire going nicely and with a Zilla you can keep the wood pile nicely stocked no problem ....