Overview - PENDING

I did not upgrade to the 4th Generation iPad, in large part due to the Apple's moving from the 30 pin dock connector to the Lightning connector. I eventually upgraded to the Lighting connector enabled first generation iPad Air in November 2014, some 12 months after its release.

 

editing in progress . . . . . .

As might be expected, the third second generation iPad had a faster processor and more RAM than its predecessor and was the first iPad to feature a Retina display. The physical size was similar to the Gen 2 with the same height and width but a slightly larger depth at  9.4mm , some 0.6mm thicker than the previous version.

Apple were not even content to limit their iPad releases to 1 a year - the Generation 3 was discontinued only 9 months after its release with the announcement of the Generation 4 model! The Gen 3 models is only supported by iOS releases up to 9.3.6 - the same as the Gen 2 model. 

	iPad 3 Overview from the first release of the iPad User Guide for iOS 5.1. There is little noticeable differences from the iPad 2 until the device is turned on, then the better quality display is evident.
In an enhancement to the original iPad, the second generation model supported a new magnetic "Smart Cover" that automatically wakes up the iPad 2 when the cover is opended and puts it to sleep when the cover is closed. I purchased one of the leather Apple Smart Covers as shown here. The same cover worked with 2nd, 3rd and 4th Generation iPads.
The UK charger for the 1st Generation iPad, consisting of a "base" with UK 3-pin plug that mates with a 5VDC/10W USB power output for connection to the USB to Apple 30-pin connector cable. It is possible to charge the iPad from the standard USB port of a laptop, but the USB 2.0 standard only allows for 500mA to be supplied by the USB port and the iPad will not charge at the same time as it is being used on power from a standard USB port. The same charger block was supplied with the 3rd Generation iPad too.

Released	October 2013
Discontinued	March 2016
Obtained by me	November 2014
Apple SoC Version	Apple A5X
Processor Architecture	ARM Cortex-A9
CPU Clock Speed	1 GHz Quad Core
Graphics Core	PowerVR SGX543MP4
RAM	1 GB LPDDR2 RAM
Flash Memory Size Options	16 GB / 32 GB / 64 GB
Connectivity Options	Model A1430 WiFi only Model A1430 WiFi + 4G Model A1430  CDMA (Verizon)
Operating System at release	At release iOS 5.1 Highest supported iOS 9.3.6
Cameras	Front Video: VGA up to 30 frame/s with audio Still : VGA-quality, 0.3 MP  Rear  Video: 1080p up to 30 frame/s with audio  Still: 960×720 with 5× digital zoom, 5 MP
Display Size	Inch mm Size 9.7 250
Display Resolution	2048×1536 pixels at 264 ppi (Retina Display)
Dimensions	(Portrait) Inch mm Height 9.5 241 Width 7.31 186 Depth 0.37 9.4
Weight	lb. g WiFi only 1.44 650 WiFi + 4G 1.46 660
Battery	3.7V, 43Wh, 11,560 mA·h (9-10 hours)
Apple Charger (UK Version)	Mains Power Plug   Charger (10W) A1357
Interface Connector	30-pin
Additional Sensors	Geolocation Assisted GPS   Cellular network Environment Accelerometer   Ambient light sensor   Magnetometer
Bold type signifies the model that I have (had)

 iPad 2nd Generation <<  iPad 3rd Generation  >>  iPad Air 1st Generation