The reason I ditched mine is that it doesn't keep the rain off, the water pours in within 5 minutes of it starting to rain. It's also far too big and heavy.
I bought it because I was really taken by the idea of a coat that sheds water like a thatched roof or animal fur instead of having a membrane or coating to wear out and leak, but the simple fact is that it just doesn't work. It's better if you're not carrying a rucksack, but not much. The problem is that rain runs down your back, and then when it reaches the rucksack the pressure of it against your back forces the water through the fabric because it's not proof against a static head. The same happens at the shoulders, under the straps. And it really leaks, not just soaking through gradually, it pours in so fast I can feel it running down my sides and back then drenching my trousers and underpants.
Despite the fact that it leaked from the day it was new, when the proofing should still have been intact, I tried all sorts of treatments. The Nikwax wash-in stuff was as useless as it is expensive, as were all the other wash-in ones, but a Granger's aerosol spray had some effect. The problem even with the Granger's aerosol was that the rucksack rapidly rubbed it off again, so that by the time it started raining there was none of it left, and it still leaked.
Without a rucksack to rub it off, the Grangers stuff would have been slightly more practical, if a little expensive, but by the time I'd switched from walking to cycling it was unavailable anyway.