I eventually got
this, after a bad experience with a universal case bought on Ebay that left small dents on two corners of the H2O...
I'm pretty happy with it so far, it feels nice and looks more expensive than it is. The magnets are strong, so the front cover won't open accidentally, but if you fold it back it puts the reader in sleep mode. It doesn't bother me much as I usually put a finger in between, and since the spine is not rigid, you could also fold the cover back in a way that doesn't activate the magnet.
Inside, there's a flap with a strip of velcro holding the reader in place. The opening on the front is just right for the screen.
Hope this was helpful!