In reply to neilus:
> but it seems that using a windshirt requires one to be able to predict how much/heavy any rain will be...?
Unless you're obsessed with carrying minimal gear, or never want to change your layers once you've started whatever it is you're doing, then a windshirt, weighing less than 150g and packing to the size of an apple is hardly a burden. It's not a choice of taking a windshell instead of a waterproof; it's the choice of taking a windshirt as well as a waterproof, and only wearing the waterproof when it's actually raining.
Softshells, IME, are rather tightly coupled to particular climatic and activity conditions, and aren't as versatile as a layering system including a windshirt. You can't, for instance, remove the wind resistant layer, or the insulation layer, as they're fixed parts of the garment. You can only wear or not wear the softshell, with its properties of wind resistance, water resistance, insulation and breathability. That's why there is such a huge range of things called 'softshells', each addressing a narrow range of climate & and activity, trying to find the 'perfect sweet spot'.
Post edited at 21:37