The first link below is to a youtube demo and review comparing the new Kobo Aura to the Kindle Paperwhite I. It is about 20 minutes long. I found it very helpful.
My understanding is that the new PW II will have a processor rated at the same speed as the new Aura, will have the latest e-ink which claims better contrast, a better touch screen, a few software tweaks, and an improved light. After watching the afore mentioned demo, for me, the Carta ink is the only thing that I would feel is missing from the Aura, but I doubt the improvement will be so discernible that I would regret going with the Kobo. It's not enough for me to want to buy into the Kindle world. The reports I've come across infer that other changes are minor. If that's true, this youtube demo should give a good idea of which product works for you while you keep in mind what the new PW will offer.
Link to thorough look at Aura
http://www.youtube.com/watch?v=NcC9BywDgYM
Here's a link to the new PW on Amazon US
http://www.amazon.com/gp/product/B00AWH595M/ref=fs_cl