The Surface 2 is the updated version of Surface RT while the Surface Pro 2 is the updated version of the Surface Pro.
The new Surface 2 runs on a Tegra 4 Quad Core processor, a full HD Clear Type 1080p screen, a two-step kickstand for better usage on the lap and even a second colour option in Silver. Its also claimed that it is thinner and lighter than the original Surface.
Windows RT 8.1 too has been optimized for better performance, better metro app snapping and more. It now sports a USB 3.0 port instead of a USB 2.0 on the older Surface and an extra Video Out port too, which was not present on the Surface RT. The Touch and Type covers have also been improved.
The Surface Pro 2 utilizes a new Intel Core i5 Haswell processor. Microsoft claims the Pro 2 is 20 percent faster than the Pro, and that there is a 50 percent increase to graphics performance.
Along with all the hardware upgrade, Microsoft plans to include free 200GB of SkyDrive storage for the first two years for any Surface 2 buyer, and adding to that, 1 year of Unlimited international calling to landlines in 60 countries and free Skype Wi-Fi.