I decided to build this because I had some money burning a hole in pocket, and because I hadn't updated anything in my old rig since 2013. This was my first time doing a custom loop and I learned quite a bit doing it.
I didn't really have any major issues with the build itself. The hardest part was getting the graphics card into the case because it's so big. I had to vertically mount it or it wouldn't go in the case, and did run into some trial and error trying to find a bracket that worked with fans on the bottom of the case. I ended up using the Phanteks model because the Cooler Master pushed the card up into the RAM.
Running my custom loop was also pretty easy. I was worried about doing a hard line loop, but after a few minutes I figured out the right tricks to bending and it got easier. There's a few that I would redo if I ever wanna take things apart to replace something. I ran into a snag early on with my fittings not fitting into the block on the motherboard, but it was a problem with the threading on the fittings thankfully. I ended up very carefully filing one or two down and that resolved my issue.
Overall, I'm loving it. It's a cool, quiet beast of a machine.