The keys themselves are made of hard plastic and they're fairly springy. If you're used to using Apple's Bluetooth keyboard, it's not quite as good as that, but it's got a much better feel to it than keyboards with soft, rubberized keys.
The keyboard has an instant on-off feature -- your iPad Mini automatically wakes up when you open the cover and switches to standby when you close it -- and Logitech says the keyboard has a three-month battery life based on usage of 2 hours per day. It charges via USB.
Making these smaller keyboard cases for the iPad Mini can be a challenge. The few I've tried, including the Belkin Portable Keyboard Case for the iPad Mini, have felt a little cramped and had a few other shortcomings despite an otherwise good design.
This one, too, feels a little small, and definitely takes some work to get used to (by that I mean typing fast with few errors). Those with larger hands will probably have trouble with it. However, unlike the Belkin and some other Mini keyboards, this Logitech has a dedicated apostrophe/quotes key. It's smaller than the letter keys, but it's there, which is important (with the Belkin you have to hit the function key to make an apostrophe or quote).
Like other keyboards for the iPad Mini, this product is a challenge to rate. Compared to other Mini keyboards, this Logitech is quite good and ranks among the best out there. True, you can find similar options from lesser-known brands like MiniSuit and Sharkk for significantly cheaper, but this model appears to be a step up. It has a nice design, is relatively lightweight, and is a good match for the Mini -- cosmetically, anyway.
On a more critical note, its small size doesn't make for the greatest typing experience. It's certainly usable, but I'd only get this if I was taking a lot of notes with the Mini or cranking out a lot of e-mail. (The other alternative, while a bulkier solution, is to get an external Bluetooth keyboard such as the Logitech Tablet Keyboard for iPad).
In short, I came away both impressed and marginally disappointed with the product. That translates into a very good product with some caveats. I'd suggest trying it in a store before you buy, if possible. I suspect certain folks will love it and others won't.