I think "center track" is not only "best" but is necessary in snow. I confirmed with a wrench that the older style can build up snow in the cog and cause the belt to jump. Not a problem with center track.
In my experience, in snow and ice you DO need disc brakes. I've hit my brakes and had nothing happen when riding in freezing rain and had ice buildup on the rims.
For studded tires, I have tried a few and use Nokian. The Marathon Winters caused me trouble because they have no traction side-to-side in wet heavy snow - the tread blocks go side to side giving great acceleration traction but allowing the tires to sideslip badly.
I kinda want to build a belt drive/IGH bike myself, but having ridden a cheap hybrid through 8 winters now and not having had any significant trouble, I can't really justify it.
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Work: the 8 hours that separates bike rides.