When Apple launched the iPad Air, it swiftly kicked the fourth-generation iPad to the curb, but kept the iPad 2 around as an "entry level" option. At the same time as the company has tweaked the iPhone lineup, it's also pulling a switcheroo in the tablet space -- dumping the iPad 2 and replacing it with the Retina-and-Lightning model. The unit is back on the Apple store for the same price as the Retina iPad Mini, so now it's just a decision as to what size slab your hands can carry.
Apple iPad 2
Apple iPad 4th-gen