Actually, I am a new Iliad user :-) I was looking for a largeish e-ink reader with wacom capability, and bought a used Iliad in excellent condition. I have several readers and I agree that the Iliad offers a unique experience with its 8-inch screen and handwriting support. I think the interface and usability is quite good, too. What I don't like is the weight, the slow speed, and the need for a special charger... But for a 5-year old device, this is acceptable :-)
About the leather cover: indeed it seems to be the M-Edge case you have linked. It is the genuine leather version, so I would not worry about long-term durability. Real leather is usually much more durable than faux leather. Also, at this price you can maybe afford to order two of them (I did).
As for accessibility to buttons and slots: this cover is custom-made for the Iliad, so everything is accessible, as you can see in the photos. The only action which is a little difficult is pushing the long button to the right, but you can do it with your fingernail.
I took some photos, here is the link:
https://www.dropbox.com/sh/5ywx70chw9fgo7q/ULqHaoZdcQ
I hope it helps! If you decide to buy it, let us know how you like it.