Anything Arch-based will never be as easy as Ubuntu, though that isn't to say that Manjaro and Antergos are difficult as such. Ubuntu's support out there is insane, and packages are ALWAYS available for it if not the other larger distros as well (Red Hat family). Keep in mind that Ubuntu primarily relies on its huge repositories, and it's easy to add additional PPAs where and when required. Arch relies on AUR for this stuff, which is a little more difficult as it's manual building (but still easy).
From what I've heard, Manjaro's security isn't great, however I know no further details at all.
Additionally, you're dealing with the bleeding edge, so don't expect Arch-based distros to be free of issues (that said, issues will be easy to fix and brilliantly documented).
What drivers were you using with KDE?