You don't hop around in your bivvy bag.
It doesn't need to be robust. You just need to use it carefully. The Snugpak SF is robust enough for the intended use.
Goretex three layer material is made to wear it under a heavy rucksack, Dutch M90 and British army bivvy bag are surely longer lasting than the Snugpak SF but I can't tell you how long the Snugpak SF will last although I used it surely during 6 years and all together effective 3 years of continuous use, always on a folding German army mat or other mat and with the Snugpak SF1 inside of it.
Most civil persons don't sleep 1095 nights in their outdoor sleep system. So as a civil user I used it really a lot to test it well.
The GoreTex 3 layer fabric is nevertheless more robust, but although it's the first choice for rain jackets it's a question if you really want such a robust bivvy bag or better a lighter one.
And the Snugpak SF you get new without any holes. It isn't said that you find a nearly new military bivvy bag.
The seam sealing tape is the weak point in army GoreTex clothing and bivvy bags, after a while they simply fall off. But that can be repaired, costs some money too of course. That might already happen at Dutch M90, German Flecktarn bivvy by Feuchter, British army bivvy in OD and perhaps also already in DPM. MTP versions surely are too young.
If you compare a new Goretex bivvy bag with the Snugpak SF, the new Goretex bivvy bag weighs 1000 g instead of 340g, last surely longer, is more robust and costs 400 € instead of 100€. You can get the current German army bivvy bag factory new from Carinthia. Called here sleeping bag cover, if you search it.
But if you buy 4 SF bivvy bags after each other that also will last pretty long!
But OK, the Dutch M90 and especially British army bivvy bags in MTP you can get very very cheap and if you can find one in nearly new conditions that's an outstanding good deal of course.
Younger Dutch ones in DPM made by Carithia are fine but made by Fesca relatively often the zippers break. I am not convinced about the hooped bivvy tents anyway as I doubt that you don't get problems with condensation water in them.
The French one is good but heavy and CCE doesn't blend in so well in Britain.
The OD German army ones, which are younger than the Flecktarn bivvy bags, cost used as much as the Snugpak SF new, looking identical some have the jacket fabric like the others, some already the Gas Permeable Technology membrane, what is what Carinthia currently sells new.
("GoreTex Gas durchlässige Technologie" stands on the white label inside and yes, indeed, they mean that you really can breath through the fabric, but you surely will get condensation moisture problems anyway if you do it. If you would close another bivvy bag from inside and try that you will surely die from suffocation. Attention! Always breath outside your bivvy bag!)
Would I plan a several year long world journey without option to replace my material I would buy a new Carinthia bivvy.
For my own intensive use I decided to get the Snugpak SF and don't regret the decision. Sometimes I combine it with a Defcon 5 poncho of the Italian army which weighs only 350g.
My Snugpak SF1 sleeping bag weighs 1030g.
That's in my opinion the ultimate lightweight trekking option. All is light and compact but all has a NATO stock number! For summer use additional the used German army folding mat (425 g) or new similar Multimat Adventure 4 XL (530g) and you have the lightest set up with NATO stock numbers that I know.
I am no pack horse and go for recreational hiking. This lightweight war equipment is really robust enough for my civil use.
(SF1 in SF bivvy bag fit together easily stuffed and compressed by hand well into the German made civil high quality 7 litres drybag Ortlieb PS10, that's available in black and also was available in OD, if you still can find it, I recommend to buy it.)
