The catch is figuring out what's going to stick around and what won't.

I have a Ubiquiti EdgeRouter Lite that's a little over ten years old. At the time, it was revolutionary in its ability to pump a whole lot of data over a cheap device with a lot of features - but a lot of those features weren't available in the GUI at all; you had to go CLI and learn Vyatta (of which it was a fork) to do them. It's been updated over the years and is now much easier to use as the web interface exposes a lot more functionality, but it's not part of Unifi (and never will be).

Early on, I looked at and even tried one of their AP's. 100 Mbps wired uplinks for N wireless? No thanks. Even the one that I got to test with had absolutely abysmal range. Say what you will about TP-LINK generally, but their Omada unified control system had AP's that actually worked in my house. So the early Unifi stuff wasn't anything special, and based on how they had dropped the ball on so much of their early hardware (the EdgeRouter Lite had its software on an internal USB drive that, out of warranty, failed in a way that I was only able to diagnose with a serial console cable - at least it had a port so I could monitor it during boot, and searching for the error messages found a way to replace the thumbdrive and reload the software) I had no reason to go with them.

If I were setting someone up today, with all new gear, I might go Unifi, but I have no reason to spend any time at all replacing a system that works just fine.