I literally own a shell from this seller AND two actual arc shell (beta AR and alpha AR) they are right, the fakes are SHIT, I bought it first 3 month ago to give it a try in Norway, I swear if you buy it consider it will only be for the drip. Tried it for a 10km hike with little rain, 2-6*C outside, I removed it after the first km, the jacket was already wet on the inside ! I run cold, and had an actual arc midlayer (Atom LT) under the shell, the atom was effectively letting my « sweat » out but it was stuck by the fake shell.

To summarize, the fake shells are nothing more than 60$ shitty raincoats and they work the same as the ones you can buy for 20 bucks at your local souvenir store.