The iPad was not the first tablet but it can claim sole responsibility for the explosive growth of the tablet market. Then the iPad 2 came to drastically cut the weight and double the processing power, and the iPad 3 crowned the collection with the gorgeous Retina display.
With these jumps between generations in mind, the iPad 4 feels more like a 3S. That's not entirely fair though - the new chipset offers a greatly enhanced performance. And while it looks like the exact same tablet on the outside, the Lightning connector allows the tablet to share accessories with the iPhone 5. Millions of people have upgraded to the new iPhone and not having to keep double stock of accessories is more than welcome.
As far as the hardware of the iPad 4 is concerned, it's one of the best 10" tablets available. It's the software that we have a bigger issue with - iOS 6 has many fine enhancements, but Android and Windows 8 RT feel like they're starting to pull ahead. Android in particular has been eroding the iPad's tablet dominance.
So, that's it then - the iPad 3 is discontinued in favor of the 4, but unless you have plenty of disposable income, it's probably not worth the upgrade (especially if you have to a lot of accessories you will have to replace).
With Apple's new, fast release cycle, the iPad 5 could be just around the corner and it won't feel good to buy a new tablet and see it become obsolete in a few months twice in a row.
But that doesn't mean that Apple doesn't have the iPad 3 owners covered. It's just that for them the iPad mini is the bigger draw - portable, easy to type on, better to play some games on (in terms of controls, plus lower resolution balances out the dated GPU). It's a lot cheaper than the iPad 4 ($170 for the base models) and since it shares its hardware with the iPad 2, it's probably the most enticing of the three tablets Apple offers at the moment.
For 10-or-so inch tablets, there are plenty of Androids to choose from. The biggest non-domestic threat to the iPad 4 is certainly the Google Nexus 10. Featuring a higher-res screen (300ppi against the iPad 4's 264ppi) and a next-generation chipset, the Nexus 10 is still $100 cheaper than the Apple tablet on the base level. It also runs the latest Android version and given that Nexus devices are the first to be updated it will remain like this for a while.
Then, of course, there's the S Pen-enabled Samsung Galaxy Note 10.1 for the artistic types and heavy-duty note takers out there and the Asus Transformer Pad Infinity, which has its proper hardware keyboard and FullHD screen to lean on.
For those looking for a tablet to replace their netbook, there's the new kid on the block - the Microsoft Surface. Offering those clever keyboard covers, Microsoft's first tablet promises to bring all the goodness of the Windows experience, coupled with a touch-friendly and intuitive UI to a handheld.
The Asus Vivo RT offers the same, but with a Transformer-like keyboard instead. The Samsung Ativ Tab counters with a newer and more efficient chipset - a Krait-packing Snapdragon instead of the Tegra 3 that powers the other two.
The app selection for Windows 8 RT is limited for now, but the shared core between that and the Windows 8 gives developers vast capabilities, so things are bound to improve in the future. Opting for a Windows 8 RT tablet now is a gamble, but one that might pay off handsomely in the future.
When the iPad came out, tablets were odd, rare (and clunky) beasts, now they're often top priority on people's holiday shopping lists. The iPad 4 may not be a stocking filler like those compact $200 droid tablets, but that won't prevent many people (we are talking a few million here) from buying it.
The hardware is top notch and iOS still has by far the best and biggest collection of tablet-optimized apps. For the first time though, it seems that record-doubling and tripling sales are a tad less certain for the Cupertino flagship slate. The Apple iPad 4 has to share the spotlight with the mini, and cannot count on too many iPad 3 owners getting a massive urge to upgrade.