I’ve been using a pair of Haglöfs Lizard soft shell shorts for a couple of years now, on and off the bike. They’re a stretch double weave fabric – no membrane, but closely woven so they’re quite wind and water resistant and they’ve done really well.
They’re a bit closer fitting than most mountain bike baggies, which actually means they work better when things get wet and gritty. I wear them over lycra or a liner short, use them a lot for general banging about on the cross bike.
They’ve lasted well too. The seat’s a bit faded, but mostly they’ve survived nicely.
I haven’t had good experiences with Gore’s Windstopper Soft Shell fabric in the Peak. Tried some of their 3/4s and they wore through the seat where it contacts the saddle in the space of three or four wet and gritty rides. I think it was partly the seam placement, but also because the fabric’s slightly stiff and just seems to abrade easily as a result. Similar experience with waterproof Endura shorts. They might last longer somewhere less gritty.
The whole what is soft shell thing is a mess. It’s anything from non-membrane, fairly wind and water-resistant stretch Nylon woven stuff at one end to membrane-based fabrics like Windstopper at the other, which are basically waterproof, but don’t have taped seams, so eventually leak there and from contamination. As a general rule, the more water resistant the fabric is, the less breathable it’ll be…
And wasn’t that fascinating 😐