Ryzen is a lot of hype and advertising. It isn't going to be amazing, so don't give your hopes up.
They are keeping too many facts from us, which indicates that it will have plenty of cons. They only show extremely specific benchmarks that suit their CPU's, and they do not allow anyone to show FPS or results in real world applications. They are also keeping their price very secretive. If these were all great, AMD would be bragging about them and advertising them, not hiding.
I am guessing ryzen's main improvement will be reducing their power intake and TDP. This would make more powerful chips much more viable for laptops and tablets, and it would keep them cooler in desktops. On top of this, it will allow them to make more powerful CPU's. Expect this to be the headline of ryzen, not extreme performance gains.
I am speculating that intel will have ryzen beat on single core performance per dollar, but ryzen's multicore performance per dollar will surpass intel's. Maybe depending on what you use the CPU for, one option might be better than the other.
Best case scenario for ryzen is that it becomes competetive with intel for its edge in certain applications. It is definitely not going to crush intel and make all of its processors null like some want.