"Soft shell" has come to means enough things that the term itself doesn't mean much.
If you're talking about a hard face, windstopper laminate with a fleece liner then the utility of the thing is limited to lift skiing and coffee runs.
Unlined schoeller (sp?) pants? Brilliant for everything but summer.
A lighter, stretch woven shirt like a Patagonia Traverse? Almost as windproof as a windshirt, almost as light, tougher, warmer and breaths better.
A heavier stretch woven full featured parka is the ne plus ultra of winter activities, where WPB have no place.
As depends on what you mean. All of the above are soft shells.
As to the original question, I quite like fleece. Beware the Thermawrap. It's lighter in no small part because it's not very warm! Fleece is a bit heavier, and way bulkier, but is the best insulation to have when it gets wet, dries the fastest, breaths the best, and is the most durable of all options. I'll keep my pile hoody, you keep the Primaloft.