For the sake of the poll, I'd even lump hydraulics in there too. They're different enough from MJ and RF, the only other two options.
Where would you stick EU? Pointless question, but one to consider when asking about pneumatics and hydraulics. The power system isn't as important as the concepts behind them imo.
Where would you stick EU? Pointless question, but one to consider when asking about pneumatics and hydraulics. The power system isn't as important as the concepts behind them imo.