I'm assuming you mean Polartec Powershield correct?
If so, I've owned a variety of Powershield softshells. In short, I've ended up wishing the weather would be nasty enough to wear my Arcteryx hardshell
I don't sweat a lot when I ski so I can't comment on the moisture management, but they do breath well, much better than Gore-Tex. Because of this I'm guessing it would help in your situation.
Whenever I ski my softshell is always my middle layer. I tend to buy my softshells in my true size. I like to take advantage of the slimmer alpine cuts and it lets me layer it under a hardshell more easily. If you use the softshell under a hardshell it's going to be cut down on breathability though. That said, if you want to use it primarily as an outer layer, order up a size so you can have some heavier base layers under it for when the weather is really cold.
A softshell is going to be ideal for 90% of the conditions 90% of the time, or so the saying goes. The Powershield material is surprisingly water resistant (wind resistant too), but when it's raining or snowing and you'll be out for an extended period of time in it, it will eventually seep through. Also keep in mind that if you don't have a hood, the softshell isn't going to be much of an outer layer if the weather turns nasy. Unless you have a nice water resistant hat, but even then I'd rather have a hood.
Which REI model did you get? I had the REI Groove model, basically a One with a hood. Since you've already bought the jacket you'll find most of what I just mentioned yourself. If you end up not liking the jacket just take advantage of REI's generous return policy
I gladly pay full retail at REI for items that I'm a little hesitant about, and more often than not I end up keeping them anyways.