OK, so I will start off with answering my own question
Without question, my vote goes for the Mills Dice. Why, because of the pure mechanical wizardy done to make this thing work.
The fact that you can place 3 bets at a time and it can remember up to 6 points (4, 5, 6, 8, 9, 10) over multiple throws of the dice is quite an achievement for a machine that was made in the 1930s and uses no electricity.
If you go look at articles you will see one about the Mills Dice (including a picture of the mechanism).
You can also get more information (including a vidoe of one working) by going to the online version of "Coin Op on CD". It is at
http://www.IBuyOldSlots.com/COCD