A little over a week ago I got a new portable EVSE. It’s an EVI Deluxe Dual Voltage EV Portable Smart Charger Plus, $319 from Amazon. I’ve only used it a half-dozen times, but I’m very happy with it.
You can use it on 120V or 240V, and set the current to 8, 12, or 16 amps. It comes with a L6-20 (240V, 20A) plug and two adapter cables, one to a 5-15 plug (120V, 15A, the one I use the most) the other to a 14-50 plug (50A).
At home I have a 120V 15A outlet and at work a 120V 20A outlet, which allows me to charge about 33% faster (16A vs 12A).
I really like the display. It shows the voltage at the outlet, so you can see how much it drops when you start charging (then if the size of the drop makes your uncomfortable, you can switch to a lower current). It also shows the current being drawn (so you may catch when you’re near the end of the charge and the current drops significantly). It also shows the total kilowatt-hours for the charging session and the duration of the session. Lastly, it shows the internal temperature and the charging current you selected.
So for a bit over $300 I now have a back-up EVSE that I leave in the car, while the original one stays mounted on the wall of my garage.
FYI. Judging from the display and adapter cables, I think this is electrically the same as some Khone, Evolution, and MUSTART EVSEs, and very similar to some from Zencar or Jekayla.