High end m-itx build built in to my new favorite case. I picked up the Manta because it was interesting and different, but once I saw it in person I fell in love with it. I probably won't be replacing it for a very long time. This is pretty much exclusively a gaming machine, I absolutely love playing almost anything on the Predator x34 monitor I'm currently using. I would definitely recommend it to anyone.
As for the build itself, it was pretty smooth. The Manta gives plenty of space to work in since it's a little bigger than the average m-itx case. I had no issue mounting a 240mm rad in the front and the top of the case. You'll notice in the pictures that I went the route of installing a Kraken g10 and later a Kraken g12 on the gpu. The kraken g10 was a pain to install (it always is) but the performance was definitely worth it. So when the g12 was announced I preordered immediately and couldn't be happier, the g12 is infinitely easier to install, better looking, and even lead to better cooling performance than its predecessor.
Performance wise, the gpu usually idles at about 26C, while the cpu idles at about 35C. Surprisingly, at max load I have not seen the gpu core go above 40C and the cpu never goes above 60C. (I'm using arctic mx-4 if anyone is curious)
For clocks, I'm running +25Mhz on the gpu core, +200Mhz on the memory, and 4.5Ghz on the cpu.
I haven't spent a whole lot of time benchmarking and tweaking for max performance but I got a Firestrike Extreme score of 13045 http://www.3dmark.com/fs/12340817