The Harmony Hub only allows 8 entertainment devices per hub, but also allows you to add home devices such as Hue LIghts. I only use the Amazon echo to control my hub. And of course, the echo can control those home devices like hue lights directly anyway.
I bought a second hub for my other TV. One limitation I found is that the Amazon Echo only supports one hub at a time. There are workarounds though (like assign one hub to one echo/amazon account and another hub to another amazon echo account). Or using IFTTT instead. IFTTT though has a much longer latency though so when you ask IFTT to trigger your second hub it takes a noticable amount of extra time.