To take the case apart, the manual mentions removing the six big golden screws from the ITX side and pulling the units apart. However, that is incorrect as it is in fact eight (technically nine) screws as two additional ones are used for the two longer spacers meant to hold the side panel down, and an additional big screw has to be removed to take off the gray cover completely in the first place.
I soon realized that it would have been much better to take them off the ATX side instead. Looks like FSP has also designed the mounting holes for the 40 mm spacers that attach the two halves with that in mind. The ATX side comes with round holes where it doesn't matter if the golden bits align (and could keep turning), while the openings on the ITX side are in the shape of the ends of the separators. The manual is simply wrong, and users won't know until it is too late. At this point you need to make sure everything aligns when tying down the ITX side or the spacers won't be flush with the chassis.
As I looked at the two separated halves, I also immediately noticed that FSP choose to screw the I/O for the ATX system down on the ITX half of the case even though it should have absolutely been bolted to the corresponding system half instead. Also, although FSP put all the storage drives into the ITX half, there is 40 mm of space between the two systems, which means they could have designed a system that would have allowed you to simply mount the drives of each corresponding system to the backside of the motherboard. By doing so, the same if not more possibilities for storage placements could have easily been included, and it would have allowed for enough space for a dual-ATX system, of which one would have been flipped upside down.
Both I/O panels utilize a high-quality black PCB to house buttons and plugs with flat and flexible USB cables attached to them for easy cable-routing.
The RGB "spine" sits on top of three 40 mm spacers and utilizes spacer rings on either side to keep centered as everything is assembled. The milky white plastic feels a little bit crude and easily pops open to reveal a simple RGB strip taped to the bottom edge. To diffuse the light a bit, FSP simply paintef about half an inch along the bottom of the plastic so that the light only shines through the top part. With plenty of brands offering their own take on truly diffused LED strips or smaller LEDs with a higher density, I would have loved to see a bit more engineering here.
Taking a closer look at the ATX side of things, the front is where you may mount three 120 mm fans or a 360 mm radiator. The plate may be detached, so you may assemble things outside of the confines of the chassis, which is quite great. On the back is space for an SFX or SFX-L PSU on the floor. FSP lists this as the unit meant to power the ITX system, but with today's choices of high-capacity SFX or SFX-L units, you may as well just go ahead and use it for your ATX half instead. Above that is a bracket with eight expansion slots. FSP has for some reason chosen to ship the T-Wings CMT710 with only four expansion slot covers and pre-installed a vertical GPU mount. However, to use the latter, you need to buy the riser cable separately.
The same removable frame for a radiator mount has been put on the ITX side. On top of that are the five HDD-placement opportunities of which two allow for both 2.5" as well as 3.5" storage units to be installed, while the bottom three are exclusively for 2.5" variants.
In the rear is the full size ATX PSU bracket above which you will find the space for the ITX board. FSP once again chose not to include any expansion-slot covers here.
All the cables within the FSP T-Wings CMT710 are of the default variety, but the USB 3.0 cables are flat instead of round. This is a nice touch, which makes routing them a bit easier. However, it would have been great if the USB 3.1 lead had been shaped the same way. Last but certainly not least is the motherboard header connector, so you may control the lighting of the "spine" directly through your board software.