I sympathize with the poster, as deploying my own stack should've been an easier migration from their EdgeRouter kit than it turned out to be - though wisely, I had budgeted a six hour window for a process that ultimately took ~2hrs. Ubiquiti's niche really is the "I want Enterprise features but I also don't want to be my own CCIE to run this shit," and in that sense it overachieves nicely. Does it have idiosyncrasie…
Interesting, for my part I would never build a data center (or underpin critical infrastructure) with Ubiquiti but I have a lot of it at blind remote sites and it works well enough - WAN failover, and they've built out a fair bit of downstream failover as well - shadow gateways, RPS, etc. Has replaced a lot of Meraki subscriptions.
As for data centers, I should be clear on sizing: we're talking the same sort of footprints you'd see Meraki leveraged for (Could I build a data center on Ubiquiti? Totally. Would I? That's highly dependent on the specific context.