For this review I used 32 inch US size 2 from both brands, and attempted magic loop socks.
Price. The Addis were around $16 and the Knit Picks were around $6.
Points. I'd have to both sets were about equally pointy.
Cable. I like the Knit Picks cable better. It felt like the Addi cable was too stiff, making magic loop a pain. The Knit Picks cable was much more relaxed and easier to manage.
Join. The join on the Knit Picks is a little rougher than I'd like, but it's ok. The Addi join is just a tad smoother than the Knit Picks.
My opinion. I have to go with the Knit Picks. The price of the Addis just is too high for what you get. In my opinion the Knit Picks are just as good, if not better. Also, the Addi US 2 isn't a true US 2, it's actually a US 2 1/2. That kind of annoyed me.