It actually isn't much fun to use if you're trying to make real product out of it. You need external hardware for the Program Counter and although it claims to be 1 bit, the instructions are 4 bits and only the data is one bit. Of course today you could use a FPGA for the external logic, but it would be a farce. I used 4000 series CMOS. I designed and was trying to sell a very low cost PLC.
I probably have one or two if you are interested.
I meant to say that the instructions where 4 bits -- as you say, it didn't look like much fun to use -- when did this device come out (sometime in the 1970s)? If you have one going spare i would love it for my little collection
My data book (I scanned all of them) gives the copyright of 1977. Actually, surprisingly enough, we have an almost mint second edition in our library at work!
I will scratch around at home to see if I still have and ICs.