This is my second system build; the first was in 1994; it cost more, and it was a 40 MHz'386. I've been through a few commercial systems since then. I decided to do a custom build more than a year ago and it has taken me that long to acquire the parts. This build is mostly for games and personal CAD projects.
Parts selection started with the case. I liked the horizontal motherboard orientation, removable panels, room for full-size GPU and lots of fan mountings. I was interested in something other than a standard tower-type case, and even though it has a fairly large footprint for a mini-ITX case, it's sufficiently compact for me. It is not easy to work in; the order of assembly is important and you'll frequently have to remove something to get to something else. Changes are not to be made lightly. I imagine this is true of most ITX cases, however.
For the motherboard, I liked some or the extras, but the layout of connectors and the number of fan headers was particularly appreciated. I did have to update the BIOS before it would work with the 4690K, and the BIOS flashback feature made that very easy to do.
I chose the Trident X memory because of the removable fins, in case I wanted to try to fit a large air cooler above it. Eventually I decided that it might turn out to be too difficult to get such a cooler to fit. I expect to get a 240mm all-in-one water cooler eventually. In the meantime the Cryorig has been a great improvement over the Intel stock cooler. It fits just fine in the available space. It is very quiet and allows me to run a modest overclock. I did discover that the initial speed of the fan is low enough to trigger the the board's low fan speed alarm, so I had to change that from 600 RPM to 400.
I've added the cat to the listing as requested, but as I no longer have the original packaging, I can't give too many details. I'm pretty sure it's a one-off design.