The thing is, CHAdeMO wasn't designed by the SAE, the Combo plug and J1772 were. Level 2 EVSE have been pretty reliable overall. There have been some issues with them not working (I was nearly stranded by one not working), but largely can be counted on.
I have no data on SAE Combo quick chargers.
CHAdeMO quick chargers, at least from Eaton, have been fairly reliable.
Signet units in my area were initially nearly useless, but continuous improvements have made them semi-reliable. A new user interface made a huge jump in usability, but they don't quite have their hardware shaken out just yet.
Blink always seem to be broken. Brand new units installed along the PA Turnpike worked for a couple of people and then seemed to quit.
I would like to hear more data on ChargePoint units, as they look like quality units.
The newest kid on the block in my area is NRG EVGo, installed at numerous Dunkin' Donuts around Pittsburgh and neighboring towns. With the cost of membership, I hope these are reliable units.
Compared to the reliability of a gas pump or even Tesla's Superchargers, quick chargers need a lot of work. I would like to know why we seem to have so many issues with them. It shouldn't be like this.