The Cameo 2 was just released in October of 2014. As I understand it, the only REAL difference between this one and the previous version is that the new one now has the touch screen, and the new rollers for grabbing/holding materials in place, and the cutter for material that is on a roll (like vinyl). I would highly doubt that they'll be releasing ANOTHER new machine in the next 6 months, since this one has only been since end of October.
I don't own either the Cameo (yet) or the Scan N Cut, but a friend does, and I've used both (plus I'm a longtime Cricut user). I have to say, I like the Silhouette MUCH better than the Scan N Cut. And the Silhouette seems to cut much cleaner than the Cricut. I also like the fact that you are NOT tied to having to use it with an internet connection. As long as you download your design library to your computer or a flash drive, you're good to go. That is a huge plus to me - along with fact that you don't have to buy cartridges. I'm determined to get a Cameo in the near future!