I took back a competitor's product because its three tower mesh system performed worse than just using the router my cable company gave me. I was super pleased with the X90 setup; I had a hiccup with the second unit, but it had paired on its own before I got to that step, so I can't really complain. The issue is that my speeds are terrible. Using the cable gateway, I was pulling 200Mbps in my office, and my kids were pulling half that in their bedrooms. Using the X90, I'm pulling 33Mbps in my office. The kids are doing better, but the second unit is helping that. Before, there was just the gateway feeding the whole house. 
 

setup: Xfinity 1200Mbps down, 35Mbps up

XB7 gateway has wireless turned off
redline 2.5Gb port to 2.5Gb switch with MoCA 2.5 adapter (2.5Gb ports) and main Deco unit using 2.5Gb port

all gigabit items go into the XB7 gigabit ports

Cat8 cables everywhere multigigabit is in use

downstairs has the other Deco unit with a gigabit switch on the gigabit port; wired MoCA backhaul; Decos are in AP mode since the XB7 is doing the routing. 

I'm not pulling nearly the speed of my Nest WiFi with three routers even though this is a WiFi 6 system with more 2.5Gb connections in play.

Any ideas? I really like this system and want it to work, but I can't spend this money to have worse performance.