The main disadvantage of this module is that it can't be adjusted. My module has scale about 0.98v/Octave and it is not OK for me. It needs just one more TL072 and two multi-turn trimpots. At least as the option.
The PCB layout is far from being perfect. It is impossible to use DIP-sockets with MCU. I had to solder it right to the board. There was some missing components in the kit. The PCB design requires too much wires. but this tiny circuit might be made on a single one-sided board with maximum possible amount of PCB-mounted components. The pots in my package had too long shafts pushing pot caps to extra-height about 7mm above the surface of the panel. This is sole module in my rack having such problem.
The circuit, logic and design are OK with exception of missing adjustment possibility.
By the way, you can share power between two parts of this module. There is corresponing holes in the PCB, named +12v, GND, -12v, +5v. So, there is no actual need to use both LM7805. One of these can handle enough power to feed entire 5v bus of the 6u case.
P. S. Panel design could be much more useful having any legend