Operating system and processor
The latest iPad is running iOS 6 and the Surface runs on Windows RT. Windows RT is a light version of Windows 8 and set to run on an Arm processor. Included in the Surface is Microsoft’s latest Internet Explorer 10 with and MS Office Home & Student Edition. Of course if you’re looking for a tablet that will run full Windows 8 then early next year (Q1 2013) Microsoft plans to release the MS Surface Pro.
In terms of processing speeds the iPad 4 runs on a dual-core A6X chip with quad-core graphics. The Surface on the other hand runs on quad-core processor with an Nvidia graphics chipset.
Battery life
The surface is able to run for up to 8 hours of intensive use compared to the latest iPad which is able to run for ten hours. The latest iPad also has twice the stand-by time as the MS Surface at 720 hours (30 days).