There is no fear, in fact I just completed updating my Cloud Key this morning and I am running the latest firmware releases on all my kit! The idea is to read the release notes as well as support forum to see what issues are introduced/resolved. Just common sense.
You forgot to mention the main reasons for investing in Ubiquiti - reliability and network security. Had it not been for Escum I would be running for over a year without having to reboot because of connectivity issues etc. I might add that I was a TP-Link fanatic and with fibre connectivity, got tired of having to reboot router and wireless extenders to restore wireless connectivity. Just my experience, if you want reliability, seamless conectivity and network security then there is nothing wrong with investing in kit that can offer you the mentioned benefits.
@RonSwanson disagrees on that point. Maybe he should elaborate.
same here - evolved from two UAPs after wasting countless hours and a fair amount of money on consumer crap from incredible. 