We have just undertaken our first long trip of 150 miles each way in the i3 and we now know that the 'i' stands for... irony.
Our first EV resulted in the most petrol stops we have ever completed in any car in one trip! Reason: sparse Chargemaster network which are non-existent at motorway service areas which seem to be the province of Tesla (ranks of nice shiny new charging units) and Ecotricity. After signing with Chargemaster, we tried to use their units but either failed to find them (many in industrial estates) which for us were useless, non-functional/blocked by other parked ICE-cars. We spent an undue amount of time trying to find something suitable and came to the conclusion that to be any use at all, they must be rapid-charge DC or combo so that you can have a driving break of reasonable time whist getting juiced up to 80% or so.
We decided to park our bias for Chargemaster and attempt to use one of the rapid DC chargers from Ecotricity at Oxford Services on a pay-as-you-go basis but their 'pump' as they call it was broken and I spent about 40 minutes on the phone trying to help them sort that out so that we could eventually use it. We failed and limped away using our range extender. In fact the whole trip not once did we manage to stuff so much as one ampere into our machine. The REX did all the work.
There remains a colossal amount of work and investment before EVs are serious transport for anything other than local running. That is if you cannot afford a Tesla Model S.
I should state that we are new to all this and the trip was actually an experiment for us. I fully expect a barrage of "you should have done this or that...." and that we - and maybe others will learn for next time.