The biggest drawback for me is that it cannot accept wireless Xbox Series controllers, just wired.Other than that it works great.
In addition to what it advertised (PS3, PS4, Switch, Windows, Linux) I have also confirmed it works on Android 10.Controllers pair very easily- in many cases it's faster to pair controllers to the adapter than it is to pair directly to the console. Getting both JoyCons L and R connected at the same takes a bit of finessing, but this is something that is not even possible at all on a regular Bluetooth connection so this is still great.I have not noticed a significant increase in input lag, but there probably is some.