I got one of the cheap micro-USB keyboard cases, but although the keyboard was fine, I wasn't happy with how much bigger and thicker the case made it -then I discovered that the three lugs holding the Linx were metal under the plastic, and the sharp edges of the tabs weren't covered in plastic, just some black rubber paint, and they were starting to scratch the edges of the tablet. This wasn't good because I wanted to be able to switch between a keyboard folio and a slip case, and it seemed like the more often I took it in and out of the case, the more opportunity for it to get scratched.
So I had a look at more expensive keyboard cases and ended up getting this Belkin one: http://www.amazon.co.uk/gp/product/B00CY9XHB4
It's made for the Nexus 7 but my Linx fitted firmly into the elasticated corners, the keyboard paired with the Linx (although you do have to give it plenty of time when it moves on to the "Installing...." stage - it was probably a couple of minutes but it felt a lot longer!).
Has a very high quality feel throughout, much slimmer and not much bigger than the tablet, plus it holds the tablet screen well away from the keyboard case.
Downsides? Well, ~ and # aren't marked on the keys, but [Fn]+J and [Fn]+K produce the characters so it doesn't worry me. The left elastic mount covers the USB socket completely, but I discovered that on the probably infrequent occasions I need to use the USB it's easy to pop the tablet out an stand it in the natural slot between the mounts (supporting its back), and the top of the keyboard block stopping it from moving forward. Looks very slick, and uses magnets to hold it closed or in the stand position. Also easy to fold round behind the tablet if I want to just use it as a portrait tablet without using the keyboard - doesn't get bulky in that position.
The other item I got was a slip case: http://www.amazon.co.uk/gp/product/B00D9VAAG6
Very slimline, dark brown synthetic leather with a lighter brown microfibre lining, and although it's made for the Nexus 7, it fits the Linx perfectly, not too loose or too tight.