If you go into your local Tesco you can have a feel of those lovely leather Kindle covers that cost about £30. When I ordered this cover for less than a tenner I didn't expect much even though the reviews were largely appreciative. When it arrived I thought they'd sent me one of those Kindle beauties by mistake - this cover is top quality.
It arrived with a foam inner to hold the cover's shape during delivery, pull it out, pop in your Nexus 7 and top banana. It has a clever hidden velcro flap which you can tighten round the back to hold the tablet very firmly in place (the user who said their's was loose can't have tightened it sufficiently IMHO). It is sturdy but not too thick, all the holes are in the right places & the front magnetic cover is reassuringly strong (& succeeds in turning the screen off every time when you close it). I can't imagine a much better case than this in the future, especially at the low price that I was charged. Fully recommended.