i've had a Snugpack Softie shirt, and while it was great for standing around in chilly winds, it wasn't as good as a Buffalo S6/Mountain shirt at coping with standing around in chilly winds with a bit of light rain/sleet added in for good measure.
it was warmer than the buffalo in dry conditions, but less able to cope with any dampness.
after it got wrecked i just used an Army issue 'Softie' jacket clone which i found to be as good as the Softie Shirt at what it was supposed to do - personally i'd recommoned it as the solution to your problem - its called the 'Thermal Jacket', costs about £30 new on fleabay and will be adveristised as 'Army softie jacket' or some such..
mine is a medium, it fits easily over a baselayer and 100wt fleece and goes well passed my bum, keeping me lovely and toasty - i'm 5'8'' with a 43'' chest and a ridiculously long back. it compreeses wthout fuss into an Exped (Small) 5L drybag.