EPS (Electronic Power Steering) is better than HPS (Hydraulic Power Steering)
Reasons are:
1) HPS is installed in engine, hence things becomes too congested because you would already be having a CNG kit in your engine bay. It will become difficult for the mechanic to work on your engine. EPS is installed in steering column, so no space issues.
2) HPS requires proper maintenance like checking Power Steering oil, changing belt etc. EPS doesn't have oil or belts to change. So you can safely say that EPS is trouble free.
3) HPS is being driven by engine. Its belt is taking transmission from engine. Just like A/C compressor belt is connected to engine with the help of pulley. So there is a little bit loss of power. Whereas EPS is electronically controlled. Its taking power from battery, so no loss of power.
4) The most important thing is that HPS is always working, taking energy from your car's engine whereas EPS works only when you want to turn your car.
5) EPS is controlled by your vehicle's speed. At low speed it makes your steering very soft, hence easy to turn and at high speed it makes your steering hard, hence it is safe.
Nowadays most of the modern cars are coming with EPS.