The iPad mini has around 60 percent of the surface area of the iPad 4 (not its technical name, but you'll still hear it). The iPad mini sports narrower bezels on the sides, which Apple used to make the device easier to hold in one hand.
The real star of this show may be the iPad mini's thickness. It measures at just 7.2 mm (0.28 in), making it 0.4 mm (0.01 in) thinner than the iPhone 5.
The iPad mini's other big advantage is its weight. At 308 g (10.86 oz), it has less than half the heft of the 4th-gen iPad.
Here's one the biggest advantages for the big brother. Though the iPad mini's 1024 x 768 resolution should look sharp crunched into a 7.9-inch display, it doesn't compare to the 4th-gen iPad's leading display. It has four times the pixels of the smaller iPad, and over 100 extra pixels packed into each inch.
This is another big advantage for the iPad 4. It takes the speedy A6 chip from the iPhone 5 and adds quad core graphics.
We're left to guess the clock speeds. But the A5 in the iPad 2 was clocked at 1 GHz, so that's a fair estimate for the iPad mini. Additionally, the iPhone 5's A6 was rumored to dynamically clock itself up to 1.3 GHz, so we're taking a stab that the 4th-gen iPad sees the same speeds.
We're taking another liberty here, as 512 MB of RAM for the iPad mini is unconfirmed. As it has many of the same internals as the iPad 2, though, it's the smart bet. The new iPad should retain the 1 GB of RAM from the 3rd-gen iPad.
Some people predicted that Apple would offer the iPad mini in a dirt-cheap 8 GB model, but the company stuck with its familiar options: 16 GB, 32 GB, and 64 GB.
All is even here as well. Both devices are available in Wi-Fi-only and Wi-Fi with 3G/LTE models. With both new models, Apple also expanded the supported global carriers (including Sprint in the U.S.).
Both tablets also share the same cameras. They aren't going to win any shootouts against high-end smartphones, but they're as good as most people would need in a tablet.
The battery hardware is much bigger in the iPad 4, but it's powering a display with 4X the pixels. This leads Apple to give identical estimates for the two devices' uptimes.
The iPad mini has two advantages over the larger iPad: price and portability. Though it won't exactly slip into a pants pocket like a smartphone will, the ultra-light mini could disappear in a purse or jacket pocket.
Though it's a more powerful device, the full-sized iPad's killer feature is still its spacious Retina Display. Books, movies, and web pages will all have a larger, sharper canvas on the 9.7-inch display of the 4th-gen iPad.
If you already own a full-sized iPad, you probably don't need the iPad mini. It's designed for those who are willing to sacrifice real estate and power for the sake of portability and affordability.