I've had Deco for years now and generally been fine. However I suspect a recent firmware update has rendered the network unusable. My setup is x90 main (ground floor) x90 (upstairs) linked by ethernet

I had a four unit deco M5 network that was working ok but had some dead spots. I installed a new Ethernet cable which gave me the opportunity to re-jig everything and buy 2 deco x90's. the cable speed