While the device is meant to succeed the Apple iPad 3 we feel its more of a refreshed model aimed at unifying the iOS device lineup by including a Lightning docking port. Other than that it has the same design as the iPad 3 and we wouldn’t consider it outdated just yet.
Despite the lack of changes, the iPad 4 is still probably the best tablet in the market in terms of performance, design and usability and well worth the $500 baseline investment.
You can read a detailed review of the Apple iPad 4 on PhoneArena.