The Logitech Ultrathin Keyboard Cover is the thinnest iPad keyboard cover I've encountered. Even at its thickest point, the keyboard cover is just shy of the thickness of the third-generation iPad, and it's more tapered, too. Interestingly, the oldest version of the Ultrathin for the iPad 2/3/4 is £89, while the version for the iPad Air is only £69.99 and the Air 2 is £85. Pricing aside though, the Ultrathin provided one of the best typing experiences in my recent tests of keyboard cases.
The keyboard is cleverly designed, staying on by using the same magnetic hinge and edge magnets that the Apple Smart Cover uses. That also means it provides the same back coverage as the Apple Smart Cover does--none.
To use the keyboard, you have to detach the iPad from the hinge (that, using magnets, pops up as you slide your iPad towards it) and place it into the slot behind the keyboard. This slot also has magnets in it to hold the iPad in place; the magnets are strong enough that if you pick up the iPad, the keyboard remains attached. To disengage the magnets, you simply tilt the iPad forward, which makes it easy to lift out.
The bottom of the cover is aluminum, which matches the back of the iPad; together, the cover and iPad look like a single integrated unit. The top is a glossy black plastic, which matches the bezel of the black iPad but collects fingerprints like crazy. The matte-black plastic keys stay clean-looking, at least. With the addition of the iPad Air 2 case, Logitech decided to offer it in both black and white to have the same integrated unit illusion with the white & silver iPad.
On the back of the right side you'll find a connect button, an on/off switch, and a Micro-USB port for charging. The rest of the cover is very clean and minimalist. The lack of rubber feet on the bottom leaves the case feeling a little slippery in the lap; the smoothness seems likely to lead to a scratched-up bottom surface over time.
For such a slim keyboard, the key travel is reasonable: It definitely feels flat compared with thicker keyboards, but it offers a sufficient amount of solid feedback. The keys are spaced as much as they can be within the confines of the iPad's width, and it's enough to not feel cramped. The keyboard deck has zero flex during typing, and the cover has minimal flex in general, noteworthy considering how thin the keyboard is.
Here's where you really notice the difference between the various versions of the Ultrathin. In the version for the iPad 2/3/4, you'll find no separate row of function keys. Instead, the number keys double as iPad shortcuts in combination with a function key in the lower-left corner of the keyboard. When the two later versions for the Air & Air 2 were released, Logitech revised this design and now there is an extra row of keys specifically for iPad shortcuts. All keyboards have home, search, Web, on-screen keyboard toggle, word selection, and cut/copy/paste shortcuts, as well as media playback controls, volume controls, and a lock button.
Logitech created something unique with the Ultrathin and has constantly improved it with every new generation of iPad. Its use of magnets sets it apart in a world of folio-style keyboard cases, and makes it the thinnest keyboard cover available with such comfortable typing. If you don't mind leaving the iPad's back exposed, or adding a slipcover for transport, this is the iPad keyboard to get.