Pics are here!
All the parts I've had ordered. They are rough around the edges, but that was to be expected. They were printed with a standard PETG filament using a 300 micron layer height. They do feel tough for their weight at least!
In the first photo I've already screwed the front and bottom pieces together. The holes were made just small enough to be threaded with metal screws.
Unfortunately there is also some warping on the parts which led to other pieces not fitting without using a lot of force and filing on the end joints. Here is an example shown on the back piece.
Top piece, also underwent some warping on one side.
Here is the better side of the bottom piece where the printing layer adhered better. The opposite side looks rougher by comparison.
On the plus side, the measurements for the back piece, which is probably most complex part of the case, are mostly spot on. If it were not for the warping, the mobo tray would also fit flawlessly.
Here is the GPU installed to the back, using one thumbscrew. The tabs at the bottom slide in perfectly with the bracket holder. It is very stable in this position.
The back side aligns well, too. All the ports are easily accessible.
All in all, these pieces were satisfactory for a prototype build. I'm still having trouble joining the back to the bottom. I didn't take account how much tolerances would be off with such a layer height. Also, a lot of the warping is most likely due to the preference of having the parts printed vertically on their shortest edge so all the layer lines are parallel along the entire case. The downside is that it adds on many more vertical layers, and requires many more supports in this orientation.
With higher quality material and smaller layer height, I may decide to print all of them in their flattest orientation as it may be better to ensure consistency in parts quality.