What are they?
"Lightweight" (300 - 400gms depending on size) boot / shoe "chains" WITH spikes
Background:
Recommended by a mate from the east coast of the USA. (had never seen them in Oz)
Researched em and they SAY they are OK for rock, concretes, scree, ice, snow.
Bought four pairs from http://www.kahtoola.com/microspikes.html - worked out to $90 each including freight

Incredibly they were ordered last Monday night and were delivered Friday...
Why?
Heading off on the OT in mid September. Last two times we were in that area in "winter" the duck boarding and shaded sections of track were very icy and treacherous. Fell over a few times and travel times were very slow as my wife hates "slipping".
Test
Went to Falls Creek in Vic this weekend - family ski trip - they ski and have fun - I ski slowly and pay (not so much fun)
Conditions Friday snowy and icy and very slippery on the roads etc around the village.
Threw on our Microspikes and they were great.
1) Really easy to put on (almost one handed)
2) Did not feel too weird to wear on solid surfaces like road and gravel - (Thought it would be like being perched up in the air on unstable chains)
3) Worked a treat on icy surfaces. Just like walking normally
4) Worked really well on compressed / icy snow (like you get on duck boarding) Including one section that was almost a 40 degree angle.
5) Did not move around or slip off the boot - just held in position
Possible risks/ problems / issues
- This was an hour long test in "civilised" conditions - no pack or tree roots or bog holes - therefore untested in rough conditions (not that the OT is very rough)
- not sure of durability of (to quote) "tough elastomer shoe harness" if hooked in branches , roots etc. It does fit very snugly to your boot / shoe
- NOT designed to replace snow shoes in deep snow - bought em to improve traction where snow shoes are a pain i.e. wearing big and clumpy duck like feet trying to walk up an icy rock face or down a very slippery section of duck boarding
Conclusion
- Look the goods for us as even if we increase my wife's speed by 20% they are worth every $$
- adding another 400g is acceptable if we can save a few falls and bruises
- will probably still take snow shoes (we have Yowies and have used them in the area before)
- will do a follow up on how they go