First issue, was getting some - couldn't find anyone in Australia who even admitted they existed. Anyway, with the help of one of our US members (thanks mate!), I managed to get a pair in my size and on my feet in early July.
Construction is a meld between Salomon's hiking boots and their running shoes. Materials are non waterproof, the upper mesh panels are quite fine and there is a sort of exoskeleton attached to the outside of the shoe to maintain the shape.

The sole is shock absorbent but has good stability. There is an insert in the sole designed to add 'spring' for increased 'exit energy'


The lacing employs Salomon's 'quicklace' which is a fine Kevlar lace with a fancy cordlock and stow panel. The eyelets are aluminium. I was skeptical of these for trail use, but in retrospect I find them quick to 'tie' and have had nil problems with them loosening and there is no apparent lace wear as yet. They are a bit tight for me when putting them on as I have quite an unusually wide entry size (top of foot to back of heel) and this can cause problems even with normal lace boots with gusseted tounges.

Weight. 390g each, 780g the pair. The Fastpackers are 490g each, my Scarpas (ZG65) are 760g each.
Comfort. Very comfortable. Hard to describe, but the closest I can think of is that these feel like a nice pair of uggboots on your foot. The foot is held snugly and firmly but softly. They have a good balance between comfort and feel - I can just feel larger stones and rocks through the sole, but not pebbles. I have not experienced the forefoot twist when walking across a slope or rocky terrain in these that I have in runners or shoes with less torsional stiffness in their soles. There is no waterproofing whatsoever in this shoe, so when it rains or you walk through wet grass, you will get wet feet. On the upside, they dry out quickly and the materials used in the inside of the shoe tend not to hold water so a complete dry out is possible in a short space of time.
Wear. No sign to date. I estimate these have done about 450km on the local trails so far. Sorry for the included dirt in the photos

Salomon has released a new version in Europe and the US in time for the northern winter, called the Synapse CS WP. These employ their 'Climashield' fabric. Not sure how absolutely waterproof they will be, but might be worth a try. If I find some for a good price I will have a shot at them as well.
There are also standard shoe height versions of the Synapse which I haven't investigated as yet.