The K810's other key feature is its Bluetooth functionality. Apple's and Microsoft's keyboards pair with one device at a time. This keyboard (like Logitech's Wireless Solar Keyboard K760) will pair with up to three different devices.
The generic benefit of that multipairing is that you can easily move the K810 between paired devices. You can use it with a desktop and then bring it with you when you switch to a tablet. You can use it with a PlayStation 3 or a living-room PC. Multiple-tablet households or workplaces might also appreciate the K810.
The process of pairing the K810 with another device is simple. Hold down one of the three Bluetooth hot keys on the function row to put the keyboard in pairing mode, then put the device you want to pair it with in discovery mode. Once the keyboard shows up on the list of available devices, select it and you'll receive a key code to type. Enter the numbers, hit Enter, and you've made a match.
If you want to replace a device you've already paired with the K810, simply hold down the appropriate hot key to put it back into pairing mode.
This process worked seamlessly on every device I tried. That doesn't mean this keyboard necessarily makes sense to use with every device.
You'll want to make sure you have a stand to hold your tablet or smartphone upright, for one thing. Unlike Microsoft's Wedge keyboard, the K810 does not include one.
Those devices also present the dilemma wherein the keyboard works well for typing within an application, but you can't navigate around without reaching over to touch the screen. That might be belaboring the obvious, but in the familiar zone of typing on a keyboard, you might feel frustrated by the fact that you don't also have immediate cursor control.
A "home button" function key on the K810 can at least bring you back to the home screen on any tablet device. And in Android, when you start typing on the K810, it automatically brings up the search screen. That's useful, but in general a dedicated tablet or smartphone keyboard is meant for long-form typing, making it a pretty situational accessory for those devices.
Those issues are not unique to the K810. And of course you wouldn't want to use it with a tablet or smartphone all the time. The fact that you can have it paired with multiple devices, though, makes it easy to snatch the keyboard away from a desktop that you might use it with more regularly.
For many people, the K810's $99 price tag will mark it as more of a luxury than a casual purchase. The backlight and the design will have instant appeal, but the multidevice Bluetooth pairing won't click with everyone at first. Those who do realize the potential of the multipairing function, and who have a need for it, will likely find the K810 uncommonly useful. If you can live without backlighting, you can get multipairing for less with Logitech's $80 solar-powered K760. Apple's and Microsoft's Bluetooth keyboards are cheaper still, and although they will pair with only one Bluetooth device at a time, they're no less effective in providing the basics of wireless typing.