In the past 6 months a lot of the popular apps got tagged as 'bad' for various reasons, not many of them clear except in the form of "remove them, the hub runs quickly again."
Therefore, about an hour after I decided to convert my "development hub" into an "upstairs hub" and thinking through the utility of Link to Hub, I saw I'd have complications with certain apps/integrations. Alexa and Google (Chromecast) were the first on my list because neither supports multiple hubs on one account. I also thought HomeBridge and Lutron were on that list but eventually determined that to not be true. I decided a third hub as some form of 'coordinator' of those apps that could exist on one Hub AND were tagged as 'bad'. (Homebridge is running on the third hub, but Lutron remains on both the other hubs.)
At the time I borrowed a new hub from a friend that hadn't even gotten around to unpacking it. I knew that if I was going to give it back, I'd have to get that 'coordinator function' moved back onto one of the two remaining hubs.
I like how it's working out though.. I may not go back to just two hubs. I'd say it's 90% unlikely I'll reduce to two. I like that the two hubs that have the radios (coordinator doesn't have the stick plugged in,) can't have Apps blamed on them. I like that I can contact support and not have to spend time on removing apps.
I like having double the radio meshes. I like that each Hub is handling a reduced set of devices and that it can spend more time on keeping those radio's unclogged.