Don't but the M9PlusV2
My home has too much concrete and metal in the walls and between the floors so I decided to buy a few M5s about a year ago. Installed 7 of them throughout the house (all using ethernet backhaul to connect to each other) and was very happy with the overall coverage and performance. When my daughters boyfriend moved in, the usage of the WiFi network shot up and the M5s became somewhat unstable. I wanted to resolve this by switching 3 of them (the main Deco and one for every floor) to the M9Plus V2.
I was not very amused when I noticed that the current firmware on the M9Plus V2 is a downgrade from the one on the M5 when it comes to options. But what really shocked me is that they are extremely unstable. I read many threads about the new upcoming firmware for the V2 which is already many months late and I noticed that, where TP Link was responsive at first they are absent in the discussions currently. Someone posted a link to the beta firmware but that link didn't work anymore. So what to do when you spend money on something that doesn't work and where the vendor is not providing the fixes or support needed? You return the item.
I do not recommend this unit until TP Link gets the new firmware out. For my home I decided to replace all my Decos (including the M5s) for another brand.