i have two mini's iPad4, ipod, iPod touch, iPhone 4 and 5s, amoung other apple products and my iPhone 4 and touch outperforms the ipad mini's now. The most recent issue appears after second to last update. Mini screen goes black, Siri, sound camera, screen shot, all still work. When I press the top power button twice the login screen appears and you can log in again, however not for long And it happens all over. The black screen is backlit. I removed autolock to no avail.
I would not be surprised if miscoding is behind massive performance drops in older sound products. Apple was a quality but profits are now before product...
With being heavily invested in Apple and in unison with my children's education, leaves me thinking of alternatives, as the Apple Brand becomes tainted and their commitment to resolving known issue fade, so too does my faith in their products & services.