Microsoft attempts to make Surface more attractive to content creators by offering Touch Cover and Type Cover, the optional integrated keyboards starting at $120 that connect magnetically and double as a display cover. While Apple provides no keyboard solution of its own, there's clearly no shortage of third-party keyboards for iPad with features, functions and prices to fit just about every budget.
Apple has famously kept USB ports and data-card readers from of its iOS devices to limit the movement of files that it cannot control. This is not so with Surface Pro, which includes a full-size USB 3.0 slot and a microSDXC card reader. Surface Pro delivers a Mini DisplayPort that can drive 2,560 x 1,440, but it doesn't include the $40 video adapter. Apple also offers wireless video mirroring and output to second- and third-gen Apple TV devices.
The input/output category is a wash; neither platform offers a better value.