The Logitech K400+ isn't like a regular keyboard — in addition to a few dozen keys you also get a trackpad to the side with a pair of mouse buttons. It's great for small spaces, but where it really shines is in the living room.
Using a PC in the living room isn't new, but using a keyboard and mouse in the living room remains a pretty awkward experience. That's mostly down to the mouse, since you need some kind of surface to use it on.
A home theater PC (HTPC) can be a wonderful thing, and using a keyboard like this makes interacting with it so much better. Setting up is a breeze since all you need to do is attach the wireless dongle to a free USB port on your PC.
This type of keyboard won't be perhaps as nice to use outside of the living room. While it looks decent and feels sturdy, it lacks any real height adjustment. If you're not comfortable typing basically flat against the desk, you won't like this at all. But Logitech even markets it as for the TV, so you know what you're getting into.
The K400+ is made up of mostly full sized keys, though you lose out thanks to the space constraints in some areas. The left-hand shift key is no bigger than any of the regular letter keys, the enter button is tall and slim and the backspace key is pretty tiny as well. You also have a split up and down arrow key.
The K400+ doesn't really come into its own as a desk-based keyboard. As one of those, it's pretty average, and you can do much better for the money, even if you're tight on space.
Where this keyboard comes into its own is when you move away from the desk. For one it's incredibly light, perfect for sitting on your lap while you're on the couch. It's nicely sized, too, with the trackpad perfectly placed. The downside is it's not going to work out very well for left-handers.
As far as the keys and the trackpad go, they're not bad given the fairly low price. You get good key travel and very little noise (nice for living room use), and while this isn't exactly a precision trackpad, the biggest criticism is that it's a bit too small. You do have dedicated volume keys, though, as well as functions on other keys for controlling media. And that's basically why you'd want one of these.
What's also excellent about this keyboard is the battery life. There are no ports to recharge, it just takes regular AA batteries and lasts for up to 18 months at a time. That's excellent, because how often do you change the batteries in your TV remote? Same deal.
So, the bottom line. If you have a HTPC in your living room, at just $25 this is an excellent way of interacting with it. For extended periods of typing you might get a little frustrated, but on balance it's a great buy.
And it's definitely better than trying to use a keyboard and a separate mouse just to find something to watch in Plex.
