This is my second build and first mATX (i5 - 2500k / ATX before). The whole process was pretty smooth, including the GPU and non-k CPU overclocking. I primarily use the machine for FPGA development and to remote into more powerful linux machines. Also, I am a casual 1080p gamer (GTA V / Fallout 4). I really enjoyed working with the air 240, a big upgrade over my previous Antec Three Hundred. I probably could have gone with a more powerful GPU, but I am definitely going to upgrade to Pascal or Arctic Islands (with HBM hopefully) when they're released. Maybe to 1440p then as well.
Edit: Achieved a 4.608 GHz overclock at 1.38V as well!