I have one. I got a plain black cover with an amber case. I love the case. It is very well built out of excellent materials. My only (small) criticisms are the alignmnt of the camera hole and the mic port. The camera hole is a little off center but doesnt affect use of the camera. Same for the mic port.
The cover itself... The materials are great quality. The construction is top notch. The design... not so much. It works well in viewing position, although I have some concerns it will fall (did once, no damage). In typing it doesnt work. They designed the cover to fold opposite of the Apple one (with the screen side in to protect it). When typing, the magnets give way and the iPad slides to the desktop. Also, when in either the typing or viewing orientation, the cover is bowed as the magnets reach to the spine and the corners are left about 1/4" behind. Now, that is with the case. I would expect that without the case you will still have the typing issues where the magnets dont hold.
I would not buy the cover by itself. Too expensive, and the design doesnt work. I WOULD get the cover as part of the case, but I would (and am) go back to Grove and ask them to resolve the issues with the cover.