@D511:
Also is it worth using? Has anyone tried it and does it work?
The answers to these questions are extremely subjective (and you also have to be more clear on what you mean by does it work
).
If you ask the person who spent 5 on a single roll turn 1 and gets Heavy Bombers or Shipyards, then yes, it is worth it. If you talk to the person who spends on one or more rolls every turn and gets nothing (or ends up with War Bonds), then no. It comes down to how much you enjoy having your games influenced by luck. If you elect to use the tech tokens rule, you can minimize the luck dependency to some degree, but it will remain high.
Personally, I would be very unlikely to play a tech game if the outcome mattered to me since I am one of those easily frustrated by uneven dice results.