I do know somebody who has bought one and I have seen it in the flesh as it were. The guy that bought it told me that while he rearely uses it becuse he prefers a hammock but that he slept out in it one night with a tarp over him and he woke up to find the whole area covered in snow. He was warm and dry. The time I saw this bivi bag was in a woods in the hills of Wicklow in at least -4 last year. He was sleeping in a hammock on this particular night. As far as I could see his sleeping bag was a Vango, he had a standard roll mat and had used the bivi bag as an extra layer. He slept very well and told us that he was not cold during the night and I have no reason not to believe him. To put this in perspective I was in a lightweight 2 man tent, lying on a thermarest, sleeping in a snugpak softie elite 3 sleeping bag, all expensive gear over here, and I woke up cold and had to use spare clothing to get through the night.
If you were planning on just using a bivi bag on its own without a tarp and a mat of some sort then it would make sense to spend a bit of money on trying to get the best you can afford, but in all honesty this bag would be an ideal entry level bivi bag for anyone living in Ireland who may be using one for the first time and may find (as many do) that they would prefer the comfort of a tent or hammock depending on conditions. In the past I have used the old olive (small) basha as a bivi bag/sleeping bag cover and breathability was not an issue because it was only snapped together but it did keep the wind off. Most people on here use a tarp over them so the bivi bag really only needs to be windproof if we were to be honest. The tarp can be set up to keep all rain out.
I am that man. All of the above is true. I have used it with a kip mat under and tarp over and woken up with the place covered in snow. I woke up saw the snow and then went back to sleep . I then slept until the smell of bacon woke me. I have used it in my hammock as an extra layer and it has helped keep me warm. I have never used it on its own to sleep out ( I always use a tarp).
I would suggest that some times its worth taking a chance.( Frost moras for £8.50 can't be any good too cheap)
If you need a bivy bag thats Gauranteed 100% breathable and waterproof then buy one that is. If you need one to try out then this maybe the one.
The guy that is selling these is part of the fourm for the Irish Army http://forum.irishmilitaryonline.com/ there is a link to the store from there I think that if he was selling junk he would be told quick enough. I am happy with my buy it will probably never get used as a stand alone sleeping system.
Why not drop the guy who is selling them a line to request further information for the bivy bag as in what type of gaurantee is offered .
Best of luck down with IPNA ,Andrew.
Hope this may help,
Tony
Tony