I would have to say that, YES snow tires are going to give you more traction, but on the other hand are not always the best decision for subarus. Like previously stated, snow tires on a Subaru are way over kill for getting around.
Plus, if you live in an area that only sees snow several times a year, studed tires are the very last thing you want on pavement! That's of course if you don't like sparks flying from your tires. A good set of skinny deap tread tires will get you through any snow, period. Don't expect WRC-like snow traction, but do know that you'll keep going forward in the direction you want.
As far as braking goes, I would hope you were driving safe enough in the first place, that you wouln't need that extra 2-5% more grip. When I talk about driving through snow at high speeds, I'm asuming that not another car is in sight and you know the road well enough. On top of that, it helps to not ride in pretracked snow. Believe me, I drive my car into the mountains at least 30 times a year. I reserve the "Bat out of hell" stuff for when I get into high elevation logging roads where I can let it loose.
I now have close to bald tires and a container of never used chains that have been sitting in the trunk for 13 years! I will admit, the tires are looking a bit rough, I'll try out some different toyos I've been checking out. The Proxy T-1 looks choice.