Number 1, the Lightning connector is smaller. That means there's more room for other stuff, and overall even more slimming.
Number 2, it's much more robust. Since it can't be forced in upside down like the 30-pin connector, it won't damage as easily, and it's not as prone to crushing. The Lightning can go in either way; it doesn't matter.
Number 3, the Lightning has smarts. It can figure out what you're trying to do with it. It's all digital and has a chip inside, so it can adapt to requirements. That doesn't mean all that much right now, but it's great for the future. As Apple pointed out, it's a matter of 'watch this space, there's more to come'.
Definitely, accessories are starting to arrive. From Apple, there's already the Lightning to USB Camera Adapter, another with an SD Card Reader (both NZ$49), a Lightning to Digital AV Adapter (NZ$75) and probably the one that will be most popular, the Lightning to 30-pin Adapter (20cm cable, NZ$59), and Apple has others.
Belkin has just released its first Lightning device in New Zealand the 10 watt/2.1 amp Car Charger with a 1.2 meter cable (Lightning at one end, car power plug aka cigarette lighter plug at the other). Expect many more such things.
In the hand
Looks wise, the iPad mini is slimmed down to the point where it really can be held in one hand, even by a little person, without feeling bulky or heavy. iOS 6.1, by the way, can differentiate between the kind of touch represented by a grip (when your thumb goes onto the screen while you are holding it) and the gestures used to operate the touch-sensitive interface, which is important with a thinner bezel around the edge of the touchscreen.
With one actually in the hand, I feel it's true what Apple claims: you don't immediately think 'this is little', you just think 'this is an iPad'. In this way, the designers have definitely succeeded.
On pure performance stakes, the iPad 4 is considerably more powerful with its A6X dual-core chip and quad-core graphics. If I was looking at a new iPad as an at-least part-time laptop replacement, I'd go with that. It also has the Retina display (in which the pixels are so small and so many, you can't see them. The definition is amazing). For this extra size and power, the cheapest iPad 4 is NZ$729 (16GB).
There is a cheaper full-size iPad the iPad 2, for $579. This doesn't have the Retina display, which rather begs the question, what was wrong with the iPad 3 with Retina display so it was pulled while the lowly 2 is still available?
But in our house, the iPad (still an original model) stays around the kitchen and lounge, being used for reading newspapers and magazines, looking things up, recipes, a little Facebook and my daughter's bouts of Draw Something. Plus it's a source of delight for the nephews and nieces when they visit. At least if we forget to hide it.
With that in mind, the mini (NZ$479 for the 16GB) is a better fit for those requirements: it's small enough to fit easily in the above scenario, but just too big to lose between the cushions. It's less imposing on the kitchen bench and easier to place, yet it's still very readable. It's still powerful enough to do all those things we require, in fact it's considerably faster than the iPad 1 we are still perfectly happy with.
Specs-wise, I won't lay too much detail on you (the Apple link above has it all), but basically the mini is 20cm x 13.47 cm compared to the iPad 4's 24.12cm x 18.57cm, and the mini is 7.2mm thick compared to 9.4mm. The mini is half the weight, though: 312 grams versus 652.
It's also half the resolution screen-wise, that's a 7.9-inch diagonal with 1024x768 pixels vs 9.7 inches packing in 2048x1536.
All round, though, you have to admit the mini is ideal for students, especially if they're already in the Apple universe. With that in mind, I will be talking to Bucklands Beach Intermediate in a couple of weeks about their implementation of iPads and where they think they will be going with it.