I've always loved Mizuno Alchemy. LOVED them. They're the only shoes that doesn't give me any problems while running. I have the Alchemy 11 (my favorite by the way).
I bought the Alchemy 12's and wore them several times and I can barely run without pain. They are hard as a rock. My shins hurt, my feet hurt, there is no cushion like the 11's. I HATE these 12's. I've ran outside once and made it a mile. Ran the treadmill for 5 (horrible). Did they change something about them? Someone mentioned that I need to "break them in" Disappointing in that my Alchemy 11's never needed broke in. I'm thinking about sending them back. I did buy another pair of the 11's b/c I really liked them that much. I could wear them for my cross training since they don't bother me for that but I have other shoes for those classes (spinning, turbo, and BodyPump).

Anyone else having issues with the 12's or is it just me? Did I just get a bad pair?