I think I would prefer the electric assist. I've dealt with two many leaky, noisy PS pumps over the years. Plus hydraulic steering steals power from the motor, which reduces the fuel mileage, a serious consideration these days. Also the electric assist takes up much less room in the engine compartment.
Maybe somebody should figure out how to adapt a stock electric assist system to these old trucks. You could sell two kits. One with the parts to adapt a junk yard find. Another with a brand new motor. From what I've read, some of the motors have been cheaply built and have not held up. Finding a good solid motor to go with the kit would make it easier to provide a guarantee.