I've tried plastic examples from all those manufacturers over the years, The best was my Cyclops Roc which was made for the Falklands conflict out of cotton canvas.
Notably, the only part of it that is starting to look a bit worn these days is the nylon and elastic snow skirt on the lid. The rest of it looks like it will last another 25 years.
As far as day packs go, this is the best I've tried yet. Far superior to the next best one I tried which was made by Karrimor over 30 years ago.
So don't talk to me about Tat.
Tat is the type of fashion bag that the plastic manufacturers turn out each year, different to the last year just for people that have to have the latest thing. They are designed for the retailers not the customers.
Good gear evolves slowly, based upon real improvements and not just this seasons fashionable colours.
It's noticeable that this bag is still in use by the German army after a great many years. The only modifications they have made is to move from leather strapping and metal buckles to cotton webbing with nylon buckles.
If it isn't broken, why fix it?