I just put together a system with this case (600C) and it's almost hard to express how happy I am with it.
It's actually 10mm wider than the 900D. !!!
Looks absolutely stunning.
Inverse ITX is looks better if you keep your PC on a stand to the right side of your desk and not on the desk (I use a single layer of some cheap plastic stacking shelves, PC on top, battery Backups below, wonderful configuration).
Built in hardware fan controller! (basically adds $20 to the value of the case, stock fans are very quiet on low. The Q must be nearing absolute silence on low fan speed).
Tool-less drive mounts everywhere, even the 5.25" bays, you could practically hot-swap optical drives if software would support it (really that should be a thing by now). Without the optical drive that space nicely hides all the extra cables on the old PSU that I used.
Tons of interior space (I'm practically allergic to standard ATX cases now). For a moment I actually started to think that the walls are too deep, but it does give you lots of room to access the GPU mounting screws.
The front door (to the optical bay) is very cool.
The only legitimate flaw I could find was the window panel latch is a bit stiff, I find myself pushing on it a bit to get it to latch fully.
I do also have a list of nitpicks:
1. Plain old, regular and uninteresting thumb screws holding on the left side (back of motherboard) panel. I know it's reliable and extremely cost efficient, but with so many things going tool-less you'd think they could come up with something more interesting, and I don't consider that panel any less important given that you need to remove it any time you access hard drives or PSU cables, pretty much any time you change anything with the system. Both doors are equally important IMO.
2. Removing the front panel for airfilter cleaning is " very fiddly" at best. Especially after you run a bunch of cables overtop of the locking tabs it can be hard to press them down and release the front panel. If the filter had been accessible without removing the panel this would be an absolute non-issue, but as-is it's going to annoy me every other year when I think about cleaning the screens.
3. Apparently tool-less GPU mounting is a thing, that should be an industry standard by now. Lead the way George!
4. Two of the cable management holes don't have rubber grommets.
5. It's not an "Obsidian" case. Given the build quality, aesthetics, features, and that it's probably a superior design over the other "Obsidian" cases in the same price range, I really have to wonder it this shouldn't have just been called a "745D" or something like that, just adding $10 worth of stuff probably would have made it a stunningly well finished package. As-is I call it just "nearly perfect".
Edited by ILoveHighDPI - 8/6/16 at 7:14pm