I bought this for my son for Christmas as well as a Pro Controller.

It's perfect for people who have an extra set of joy cons and pro controller as well, it helps rotate if you have really long gaming sessions without wanting any downtime

I tested the controller by charging it off the Switch itself, and it worked fine

If you are diligent and rotate your joycons and keep you pro controller charged you won't have issues with dead controllers

I can easily charge my spare joycons and as well my main Pro Controller for hardcore gameplay

I have the model that holds both the Joy-Cons and the Pro controller at the same time

so I really didn't need one of the the multi joy-con ones, but this is nice to charge 2 and your pro controller at once

I tried it with four joy cons and a pro controller but the lights don't come on indicating that it's charging nor do the controllers charge

The other Joy-Con and the Pro Controller charged fine

It is a very good accessory for gamers and one that I sincerely recommend for anyone that has the Pro Controller as well