iPad. A tablet is a consumption device and is not supposed to be paired up with a keyboard, because that would reduce the device's portability factor which is the main reason people buy an iPad in addition to their laptops. Android still lack high-quality tablet apps and the Microsoft RT concept is just flawed.
As for the Surface Pro 2, the 128GB version, at $999, costs the same as a 128GB MacBook Air which is certainly a more productive device than any tablet.
As for the Surface Pro 2, the 128GB version, at $999, costs the same as a 128GB MacBook Air which is certainly a more productive device than any tablet.