I just got mine and it works wonderfully. I agree with a prior review that the back of the board could use the instruction set printed on it or on a small card included with the trainer to make it more useful. Very well done!
I owned a RadioShack Microcomputer Trainer when I was a kid. I liked it so much that I wanted to build another one. So I used the schematic from the manual to find parts and build my own. Unfortunately, I could never find a replacement TMS1100 IC that would work. Fast forward to my first Arduino, I'm thinking "I wonder if I could make this thing emulate that TMS1100 IC" but I never got around to it. Then one day I see this thing on Tindie and my mind bursts for joy. Not only is it really well built, the learning material is really well done as well.
The only thing that I would ask to make this better: the source code that runs the thing and some info on how to hack/modify it.