^^^ plugging it in all the time isn't a problem for me since I'm home during the day, though. If anyone has a prius prime or vehicle of similar range I'd be interested to hear their experience.
I have a Ford Fusion Energi. It has a 20 mile all-electric range. I work 19.5 miles from home. I plug into a standard 120v outlet every time I get home.
I usually travel about 950-1000 miles between fill ups in the warmer months. Obviously, fuel tank size comes into play in that calculation. Battery range is enough that I can get 50-60mpg in standard hybrid mode on my drive into work, and then do the entire trip home in EV mode when the weather is warm. Cold temps reduce the range so that the ICE typically comes on 1-2 miles from home.
We live a few miles outside of a rural town, so trips to the store, or family's homes are almost always done in full EV mode. I bought the car with 23k miles on it and a lifetime fuel economy rating in the low-mid 40s. I'm now around 46k miles and have dragged the lifetime fuel economy up to 90.0mpg. That has dropped a few mpg each winter with colder temps and shorter EV range, but it has thus far seen enough of a gain in the warmer months to continue rising over the lifetime. Might eventually get to 95-100mpg, but I think that's probably about the max I'll see with my usage.
PHEV pros:
reduced maintenance vs full ICE counterparts
smooth, quiet operation in EV mode
Using the full battery capacity (or close to it) frequently is probably a better use of natural resources than dragging a 100kwh battery around and only using 1/5 of it.
No range anxiety. It gets regular hybrid levels of fuel economy when the high voltage battery is 'empty'. This works if you can't charge at home, or if gas prices are cheap enough to be equivalent or superior to public EV charging. I paid $1.84/gal last week. Public charging can't really compete with that on a $/mile basis.
PHEV cons:
You have the complexity of an ICE and an EV powertrain combined. There are some parts removed, but still more than a full EV
Many times, the hybrid battery takes up space that reduces interior or trunk capacity. An EV on a skateboard chassis has tremendous packaging advantages by comparison.
They're not currently very common, so finding experienced service might be difficult (I've had to do nothing but a single oil change during my ownership, so perhaps service isn't a huge concern)
They can often have some unique parts that differ from the ICE vehicle that they're typically based on. These may be difficult to procure (and therefore costly) in the future.