While I love my spools, have them front and rear, they're not for everybody. If you're like me and don't run a front trackbar (YJ), a little more steering input is required. The spool wants the jeep to go straight all the time, so when you turn the steering wheel with no trackbar the steering tends to push the axle to the side before you begin turning. I don't notice it anymore, but it is there.
Then there's the idea that in every turn you are losing traction on one tire, usually the inside tire as it tries to spin faster to keep up with the outside tire. It hasn't been a problem for me, even in the snow, but it's something to be aware of so you can drive accordingly.
I expected problems in the snow but for me the spool has been very manageable, and often downright fun. Traction is great and you can have a lot of fun when you want with just a blip of the throttle.
Run a spool in the back and save the big bucks for the front, where a limited slip or a selectable locker sounds like the best option for you. If you run a TJ, you will want a limited slip or selectable for the front as any locker will tend to push the jeep straight when trying to turn (in the snow).