Been using my Prius Ev plug-in since December and it getting good results. I’m using 0,3 litre / 10 kilometre petrol and 335 Wh / 10 kilometre gives me a total cost in swedish kr of 5,04 kr. The trick of being able to charge is of course one of the major issues.
This is the way to charge at IKEA uppsala.
Contact me if you need a GSM connected electricitymeter to measure all the electricity you charge. (The extra grey box on the charging cable)