Well i can report that the jacket is indeed breathable, the material is almost similar to my OMM Kamlika jacket.
Ive worn nylon shell jackets with their very shiny interior membrane, and yes you do sweat buckets in such clothing when the outside humidity is high, but the Highlander jacket has similar properties to pertex, even though the material used is not as fine a weave as pertex.
I was caught in very heavy rain yesterday, for nearly half an hour, and this £20 bit of kit kept me dry, and free of internal moisture.
No doubt had i been walking at a very fast pace, the perspiration would have started to develop inside the jacket, but that can be said for most jackets.
Highlander have produced a very nice bit of kit, for a bargain price.
I am sure the jacket will not stand serious punishment like a full blown Goretex or similar priced coat, but for something so cheap and affordable, it will certainly last several years of constant use, and heaven forbid, if it gets lost or damaged, its not the end of the world.