I do have a soft shell, but as others have said here – I only wear it off the bike.
Pertex is a trade name for a lightweight, very tight weave nylon (not sure about the nylon bit). Plenty of other types about, mostly marketed as wind-proofs.
They're only usually heavy showerproof at best, but they breathe soooooooo much better than anything plastic membrane based, and dry quicker too.
Personally, I use a Berghaus jacket from their bike line before they abandoned bike wear – their fabric is called 'airfoil'. Its tougher and doesn't pull like Pertex can.
The thing is, if you are always looking to stay dry on a bike, you'll never be happy with any wet weather gear. The key is accepting you'll get wet, but finding something that keeps you warm and dry enough, until you get out of the weather, or you start to dry out.
I've got a proper plastic bag with holes in for when its tipping it down, but I've used it less than 5 times since 2006.