AAPL is getting crushed today after reporting revenues and earnings more or less in line with or at the generally lower end of expectations. iPad sales were specified, and were amazing (even if short of the rosier analyst calls). However, Tim Cook and Co. didn't specify the breakdown of sales between iPads and iPad minis.
Margins were also squeezed however. In many quarters the iPad mini cannibalizing the iPad is being blamed for this (along with continued iPhone 4/4S sales at the expense of iPhone 5's). Apple makes somewhat less on each mini than it does on each iPad.
Overall, as long as sales keep growing at a decent clip – which they are, unless you are among the most optimistic out there – that's a high class problem to have IMO. They continue to sell boatloads of iOS devices, further enhancing the iOS ecosystem. It's a virtuous cycle. And China has barely been tapped overall. I'm not saying the stock is or isn't fairly valued. But I'm not remotely worried about the company itself. And the iPad (including the mini) is an absolute mega-hit product.