I'm going to stick up for the Volt a bit here, both in terms of concept and implementation. I've had two of them, a first generation 2012 and a second generation 2017. My daughter now has the 2012. I got the 2017 because I wanted the longer electric range and adaptive cruise control.
Where the Volt excels above most other PHEV concepts is that it is a full fledged electric car when it has battery power and a full fledged ICE car when running on gas. By this I mean that the electric mode does not have limited speed or power compared to the engine, like the Prius does. And in ICE mode, it runs like a normal car (except you notice it doesn't have the clunkiness of shifting through gears) and has normal power and range, unlike the i3 with a range extender. With the battery full and the gas tank full, it can go over 400 miles. I like the implementation using two motors (not three) and an engine with a planetary gear set. When it needs to engage one of the clutches, it is able to speed match the friction disc before engaging, so the transmission should see minimal wear.
In terms of my use of the vehicle, I drive mostly in a city with some short interstate drives. In town, I rarely ever use gasoline. Last year I put a total of 16 gallons of gas in it and this year I put 3 gallons in it in February and 7 gallons in June. Now I'm down to half a tank. I have had the 2017 for three years now. I changed the oil when I first got it and according to the oil life meter still have 38% of my oil life left. Other than that, I have added washer fluid and fixed a flat tire. The 2012 Volt had a coolant reservoir level sensor go bad, which prevented charging of the battery. That was a pain to diagnose and fix, but GM makes the software and module programming downloads available in a way that it was cost effective to do it myself.
So the original question was PHEV or all Electric. I will probably never buy another car with an engine. However, at present I need the ability to do a 250 mile trip at the drop of a hat, even when it is 0°F and windy, in the event that my aging parents need help, and I can't afford an EV with that capability. So the Volt gives me 90% of the benefits of an EV with all of the flexibility of an ICE car.
As for the defenders of diesel engines, while you can convince me they still have a place in long haul trucking in rural places, I think they are too damaging to health to run in a city. Having a diesel bus or truck pass me when I'm riding my bicycle is noxious and choking. The pm 2.5 particles are an issue that leads to respiratory and other health problems.
Back in the 90's, I looked into what it would take to convert a car to electric and get 12 miles of range so that I could drive to work. It was possible but super expensive for a limited use vehicle. Then in 2015, I was able to buy a used car with an electric drive train that could go 38 miles on a charge, and still had an engine, for less than the cost of doing a conversion in the 90's. So I am confident that by the time I need to get my next car, there will be an all battery electric option that will meet my needs.
