Arrow, where one of the biggest speed/time differences comes into play with the inertia splitter vs the hydraulic splitter is that the inertia splitter NEVER slows down. A forked piece or knotted piece that makes the hydraulic machines grunt and slow down is still rammed through the inertia machine in the same two seconds. It is extremely rare to have to hit the same piece twice, but in those cases the piece is still split faster than the hydraulic machine gets through it.
As far as time difference in a one man scenario, the first weekend I got my Speeco splitter, working by myself,I filled my dump truck heaping full with split wood in a little under two hours. With my hydraulic splitter with the slip on 4 way wedge and two of us working, it took 3 1/2 hours for the same load the day before. The truck holds 3 full cord and we split it to fireplace size logs for our customers, so nothing is bigger than 3" square.
One other time (and money) saver is the fuel efficiency of this splitter. It holds about a half gallon of gas and runs at least 4 hours on a tank. My hydraulic splitter uses a tank every hour and ten minutes. I'm guessing the capacity of it to be 1/3 of a gallon. It may not seem like much, but in the time that I stopped to fuel the machine, I would have had several logs split on the inertia splitter.