@tasmanuk Mesh systems are much better than range extenders. I have tried range extenders in the past and although cheaper option, there are lags when transitioning from main router to wifi extender and vice-versa. In my experience, mesh systems work flawlessly, the switching is seamless and you never notice at all. Which is I guess the purpose of them.
Not all mesh systems are created equal though, so do your research before deciding what will work best for you.
I didn't personally worry too much about wifi 6 when I bought mine because I have no wifi 6 devices and the good wifi 6 mesh systems were around double the price of the Deco M9s that I picked up on the big sale day that a certain massive online retailer has. I figured by the time I have a few wifi 6 devices, those mesh systems would have come down considerably in price and probably improved a lot during the intervening period. But some people will prefer to get into wifi 6 now rather than getting wifi 5 and then having to make another purchase 2 years down the line.
I think you are looking the 3 pack of M5 vs the 2 pack of M9. The M9 are a more expensive product, has more antennas, dedicated wifi backhaul etc.
