Okay so I've built mine together in the last few evenings, here are some general impressions.
The quality of the PCB and the case is generally pretty good, though the shot peened finish on the aluminium frame is a a bit too rough for my liking. I'm relatively new to this, so I've not got a lot to compare it too, but the machine finish is not as good as, for example, the Tex Filco TKL case that I have.
Also two of the screw holes were damaged, probably during the manufacturing process. There is enough thread left so that the PCB screws in just fine and they are not visible once assembled, so I guess it's fine.
First impression is pretty good, although it's nowhere as stiff as the Filco TKL in aluminium case that has been my daily driver for the last few months (although I suspect few things will be, seeing as it's a steel plate sandwiched between blocks of aluminium. It could also be down to the stiffer springs in the ergo clears switches though. I suspect a steel plate (standard plate is aluminium) will make a bit stiffer.
Some people have said that you can move the numpad to the left of the board, but that's not true - there are no pads for soldering the boards together once you divide them, and there are ca 20 traces running between the two parts so doing it yourself will be a real pain. Also the USB port cannot be moved. What I've figured out though, is that the RSIII is designed to be completely compatible with the Lightsaver case, even down to having four downward facing LEDs the on the sides, for the downward facing LED holes on the LS. There are two more downward facing LEDs on the edge between the main keyboard and the numpad, and that hints at the purpose of the breakaway numpad. Basically the PCB is designed to fit the Octagon/75 Mini case once the numpad is removed.
It took me about two whole evenings to put it together - mostly spent stickering and lubing and changing the stock springs, and adding the SIP socket mod. I'd say it's not bad for a first time keyboard project. Now only thing left to do is clean the back side a bit with isopropanol and wait for the key caps to arrive.
Here are some crappy phone pics because I can't bothered to get the real camera out.