I believe, the most important thing you should realize, is that the charging requirements and preferences are completely different for a BEV, like the LEAF, than for a PHEV, like the Volt.
This is because when the driver of a BEV faces the option of where and how to fuel, the environmental and financial cost analysis (when not distorted by subsidies) will almost always lead to a preference for home/overnight charging, rather than using a public EVSE. The only exception is when the day’s drive exceeds the overnight charge range, in which case, the only practical option is fast charging, not the L2 public chargers, which make up the vast majority of the public EVSE today.
The preference for home/overnight charging also holds true for a PHEV like the Volt, but the much shorter electric range of PHEVs, requires the use of public charging, far more frequently, for electricity-fueled travel. However, since no electric charging at all is required , due to the on-board generator and/or traction ICEV, charging is never a necessity, but only the preferable fuel option, for a PHEV.
While the instances of BEVs using public charging will be relatively rare in comparison to PHEVs, BEVs need faster charging, to be practical for longer trips. L2s just don’t suffice, for a several hundred mile trip (as many know from the experience). The infrastructure must be fast, flexible, reliable, and available 24 hours a day, on all major highways (as gasoline is today) in order for BEVs to be widely adopted, for single-vehicle owners.
So far, no PHEV has been designed to accept charging at a faster rate than L2. And the presence of a fast charge network, would, of course, remove much of the design rationale for PHEVs, in the first place. Public L2 is much more useful for PHEVs, as, their short range is far more likely to require intraday recharging, but the charge network does not require reliability, either of access or operation, due to the on-board ICEV alternative.
Unfortunately, the prevalent model of “free” L2 charge stations, has the perverse effect of encouraging both BEV and PHEV drivers to charge at these points whenever possible, even where the true cost, both financial and to the environment, would almost always be lower, if the same vehicles were charged overnight at home, whenever this option meets range requirements.
As for overnight (home) charging of PHEVs, I don’t see L2 is often required, as L1 charging should be sufficient, in the vast majority of cases, for PHEVs, of 12 kWh or smaller, battery capacity.
Some LEAF owners have been critical of the low rate of the LEAFs on-board charger, and the L2 rate, but some others are satisfied with L1, for home charging. For me, I use L2 at home, since the upgrade I required for traveling, also meets that purpose. Otherwise, I might still be using L1, at home.
Back to your questions:
So I'm going to start by asking what sort of charging station you have at home?
Nissan L1, upgraded to 16 amp L2.
Do you take the 'portable' charger around in the car with you?
Yes, I carry the same charger as above with me, excepting short trips of under 50 miles.
Have you ever used this outside your own home?
Frequently. There very few “public’ L2 charge points within 200 miles of my home, so I utilize the portable L2 frequently, at both private homes, and commercial establishments, such as RV parks.
And have you ever used a publicly available charging station and what was your experience?
Yes. I've never seen an operating fast/DC station, and I've never been to a public L2 located where I planned to park (other than as required, by the slow L2 charger) for a long enough time to receive a significant charge, with one exception. The one public L2 located near my home, where these conditions were met, has been so unreliable, due to operational and access problems ( blocked on 4 of 5 visits, out of order 3 of 5, and accessible only limited hours) I have actually received only a few hours of public L2 charge, other than at the Local Nissan Dealership, in the last 10 months.
I was able to make the over 250 mile drive home, last May, from the San Francisco Bay Area to my home in Northern California, using public L2 and Nissan dealership charging. I suspect this might not be as quite easy today, since the L2 network has not grown, and the number of PHEVs and BEVs has increased enough since then, that I might not have access to the same (limited number of, all “free”) L2s, on the last 200 miles of this route.