Apple's iPad does not have any slots or ports to allow for additional storage capacity, but many Android tablet options do. Most of the Android tablet options, however, use the older MicroSD technology, which maxes out at 32GB. The MicroSDXC supports capacities of up to 2TB, and the slot is backwards compatible with older MicroSD and MicroSDHC cards.
The MicroSD card can be left in place to permanently expand the capacity of the tablet, or it can be swapped out as needed--for example to change out music or movie libraries, or to switch data for a project.
For the same $500 base price, the Surface RT provides twice the storage capacity as the base iPad--but Microsoft has also taken some heat over how much of that storage is used up before you even boot the device for the first time. It won't knock the iPad off its pedestal any time soon, but depending on what you want a tablet to do, the Surface RT has some features and benefits that make it unique.
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