I'm sure I'm not the first to mention this, but the USB port on the M9 Plus is useless without the ability to use it for file sharing. It's a super simple, basic feature that's available on hundreds of routers on the market (including many of TP-Link's) but for some reason is not available on the M9 Plus. 

I saw the port on the router and assumed it would be usable and was surprised to find out when I received it that it was not usable. There have been mentions in the community in the past that if enough people request it then they would consider adding it...but still nothing.

Now that the newest flagship router has a usable USB port (for $1200) I'm hoping they'll finally push that same functionality into the legacy routers as well.

I really hope TP-Link isn't going to abandon its faithful users and reserve this feature only for those elite new users willing to pay for the newest (and most expensive) rounter in their line.