Interesting discussion.
My thoughts...
Any stove will be fine for the Overland Track - the altitudes you will encounter are generally not significant enough to make any huge difference to their effectiveness. My understanding that metho Trangias are more susceptible to performance drop at altitude.
I have always used Shellite stoves, and would very much appreciate you elaborating on your horror stories regarding Shellite.
I currently have two stoves - Optimus 99 which simmers very well and is a solid performer, but is very old and I think they are made from steel now rather than alloy as mine is. I took it on a 7 day walk in 2005 and it went fine, though I did have to do a bit of maintenance on it at the Irenabyss.
The MSR Simmerlite does not simmer.
It's great for getting water to the boil, which is about all I need. If you try to get this stove to simmer, the flame is likely to go out.
You can get a low flame, or a full-on flame. But the low flame is generally too strong to simmer say a 1 litre pot of pasta, it will still boil too rapidly and burn the bottom of your food without constant stirring.
The control is on the pump, so it adjusts the pressure in the hose as well, meaning there is a slight time delay for the flame to stabilise after an adjustment (talking about low-flame adjustments).
Would be better to control the fuel closer to the jet, such as in the MSR Dragonfly.
Priming the shellite stoves is the pyrotechnic bit - once the fuel is pressurised, the tap is opened briefly to allow fuel to the stove head, that is lit to heat the tubing so that the fuel delivery will vaporise and you get a gas-like flame.
If you let too much fuel into the head for priming, you have a little camp fire going there for a while and in windy conditions that can be hazardous. In tent vestubles it is very dangerous. Much experience is required for priming shellite stoves in tent vestubles - it can be done but you want to know the characteristics of your stove pretty well before trying - better to use another option - cook outside or under a tarp is a better option. Or in the case of the Overland track, on the stainless steel counter tops provided at the huts.
An excess of shellite on my last visit to New Pelion hut, and I was able to supplement the room heating by running the stove for a while.
I have seen a report and read a story on another site about a fuel stove where the heat shield was not used, the fuel bottle heated up because the stove was unsupervised, and when the people approached the stove it exploded. Very nasty indeed! So as with all stoves, use it properly and keep an eye on it.
Having covered what I see are the aspects of Shellite from my experiences, I still prefer it. You can see exactly how much fuel you have. I have never liked the idea of gas - puncture it and your fuel is gone. I suppose the same can be said about the shellite fuel bottle, though at least it is not under pressure. I have not experienced gas so I don't really know about gas, people like them and use them, but not for me.
I covered the weight of my MSR stove and billy kit in
this topic.
I'd like to see what Tony has to add to this discussion - he's the expert!