Here's the specs:
Northstar:
Overall Length: 8.5"
Blade Length: 4.250"
Cutting Edge: 4+"
Blade Thickness: .170"
Blade Steel: A-2
Hardness: 59-60rc
Weight: 4.5 Ounces.
Aurora:
Overall Length: 9.5 Inches
Blade Length: 4.5 Inches
Blade Steel: A-2
Hardness: 58-59 rc
Blade Thickness: .170 Inch
Weight:6 Ounces
Somehow .25" if blade and .75" of handle and a whopping 1.5 ounce difference makes the Aurora "huge" to some folks and the Northstar "small".
Maybe I'm really, really strong, but 6 ounces feels like nothing. Couple that with the fact that the Aurora balances just behind the first finger, making it handle heavy, it's a very nimble blade. I don't know where the Northstar balances.
I personally, think the Northstar looks nicer, but the Aurora feels perfect. I remember asking Mike Stewart about the difference on the "other" forum, and he said they spent 2 years working on the Aurora, getting it "just right", and jokes with Reid (of Sharpshooter sheaths) that the Aurora was made for actual hands.
That being said, with all the reviews I've read of both, chances are, if you don't like one, you'll love the other. People who love the Aurora generally don't like the Northstar and vice-versa. Honestly, the shape and size of the blades is so close I can't see there being any performance difference between the two. If you already don't like one, you probably will like the other, and can probably find someone to trade with. It really comes down to personal preference.