The main thing I don't like about it is you can't change the WiFi channels nor how wide they are. 2.4GHz is a 40MHz channel. This is typically a huge no-no especially in congested areas. On top of this, the center channel is 8 which I can not change! This is 110% redicuolous and shows that they didn't have anyone who knows networking create the UI! I am contending for unused capacity across the ENTIRE 2.4GHz range!!!
It's' counter intuitive but because of WiFi congestion a 20MHz channel centered on 1, 6, or 11 is going to be significantly faster for me. Best I can get because of congestion is 30~45Mbps on a 20MHz channel. Because this Deco S4 is 40MHz on Channel 8 it has a hard time breaking 10Mbps. Shoot, even a 40MHz channel on 1, 6, or 11 would be faster.
Im giving it one star because of this. Once an update gives us an "advance wifi settings" page that lets us tweak these settings I'd give it a solid 4 stars.
Also, if you use it in router mode, Im still not sure what CPU is in the thing, but it seems pretty weak. I'd be concerned with it bogging down if you have too many sessions going on.
Luckily my client doesn't have neighboring wifi so 40MHz on whatever channel doesn't matter. The coverage is pretty solid too.