Wanted to build a silent PC that also has a small footprint. The way I achieve silence is an oversized CPU cooler, no case fan, and semi-passive PSU (and video card if needed discrete graphics).
Not many mini-ITX cases can house a Noctua NH-D15/D15S. Lian Li PC-Q33 and Fractal Design Core 500 are two of them. Q33 is much better looking IMO but if you needed higher end graphics you'd have to go with the Core 500 for compatibility. At the time of my purchase the Q33 was nowhere to find so I ended up with the Core 500. Later I picked up a Q33 as well.
The NH-D15S fits perfectly as you can see in the photos.
I have had 3 Fractal Design (Define S, Core 500, Node 202) cases by now and none of them are perfect. I always love the layout and aesthetics. But manufacturing quality of FD always disappoints me as all 3 FD cases had alignment issues. On this Core 500, the top fan/radiator bracket is not aligned properly with the rest of the frame. I have to squeeze the frame diagonally to make it fit. The design of PCI slots is also flawed due to insufficient opening. If you have a video card that has a legacy video output e.g. DVI/VGA near the top/shoulder, it can be very card to insert the video card.
SSD and memory are both chosen from Gigabyte QVL for maximum compatibility.