I've reviewed more keyboard cases than I care to remember, and many of them have been made by Logitech. They've cornered the market on sensible and well-built solutions: the best of all may be the Ultrathin Keyboard Cover, which is well-built, has a great key layout, and is nicely compact.
Logitech keeps experimenting with form, and the Keyboard Folio ($99) is the latest iteration. It's a bigger-boned flip-open-type case, with a canvas-like exterior and plastic/rubberized interior. The Bluetooth keyboard's bonded to the inner lid, while the iPad (iPad 2, 3 or 4) attaches via a flexible bracket. The Folio comes in four colors (black, blue, yellow, and pink), and yes, there's a version for the iPad Mini ($89, but arguably less useful if you extrapolate based on the Mini-sized Ultrathin Keyboard).
The Folio has an attractive look, but it's not nearly as streamlined as I'd prefer. It's lost the sexiness of the Ultrathin cover. But, it does have a little loop on the top lid for inserting the stylus of your choice. Yes, the Folio turns your iPad into a sturdy and lap-friendly portable keyboard-computer, but the total package is big, thick, and heavy: 1.38 pounds, nearly the same weight as the fourth-gen iPad. You're doubling the weight (and thickness) in your bag. Why not just bring a laptop? There's a whiff of an industrial design vibe, as if it's meant for institutional use more than consumer.
The keyboard suffers from a layout change, too: some punctuation keys have been compressed, and keys like Tab and Caps Lock on the left have been given double-duty as letter keys. It makes sense if you acknowledge how little you might use Caps Lock or Tab on an iPad, but it shifts the key layout ever so slightly, making the keyboard feel just a bit off-center. I found it disconcerting.