One of the strengths of Android is the enhanced USB host mode introduced in Honeycomb 3.1 that allows a wide variety of generic peripherals to be used on compatible devices.
Input device (HID) compatibility has been improved so you can actually see a pointer when plugging a mouse and you can also play with a joypad of your choice in games. This allows you to transfer pictures from cameras to tablets rather than through PCs. At the same time, the host mode works with flash drives and portable drives for media playback or backup purpose.
However, very few of the best tablets
or handsets running on Android come with a USB 'A' receptacle; this limits upgradeability. Sanwa from Japan now has a USB card reader dock (3,280 yen or $40 USD) that plugs into a micro-USB jack to give you dual SD slots and a full-sized USB which supplies a max. 100mA power. The latter port can handle everything from a game controller to a mouse and a keyboard. For USB mass storage and mobile scanners, Sanwa provides another micro-USB for drawing power from an auxiliary source. After seeing this in action, we wonder why the versatile USB dock doesn't come with a flip-out stand. It would have been so much more useful if there's one.
Keep in mind that the Sanwa USB reader dock
for Android only works a rather limited number of devices, including but not limited to Samsung Galaxy S2, Galaxy S3, Sony Xperia NX SO-02D; Sony Xperia acro HD IS12S; Toshiba REGZA Phone T-01D; and Sony S-series Tablet.