I live up in Seattle so it rarely gets really cold here (ha- of course as I say this we are in our second week of 30's and low 40's - ok ok thats not too cold but for here...) We do however usually get a lot of chilly rain and I go out in whatever weather there is. I got the soft shell (its an REI bike specific one) last fall for cold dry weather because I didn't have anything that was long sleeved and warm. Well, the first time I wore the softshell it absolutely poured and I was totally impressed at how dry I actually stayed. The sleeves soaked through because they have this extra breathable band that runs around the top, but everything else stayed nice and dry and toasty. On a similar ride with the breathable rain jacket I got so soaked from my own sweat that I may as well have not been wearing it. Sure they block wind, but the more plasticy jackets are noisey and they stick to me anywhere that I sweat so I get that cold clammy feeling.
summary
soft shell -pros- warm even when wet, very breathable, comfy to wear- move nicely with your body more like a shirt, useful when cold but not raining too,-cons- not really all that stuffable - if I wear it I have to keep it on, because it does not fit in my pocket, not brightly colored, but does have reflecty strips, longer time to dry if it does get wet.
breathable rain jacket -pros- easier to stuff, usually bright colors for better visibility in bad conditions.-cons- sweat box effect even with pit zips wide open, not very warm - clammy cold feeling, crinkely and stiff and catches a lot of wind.
Usually in the summer if it rains, I just buck up and get wet, but I suppose if I knew that it was going to rain and I knew that I was going to be out in it the whole day, I would wear the gortex jacket. The soft shell would be way way to hot.
