I used pure Arch for a few last years as a main system on my laptop (installed and configured in console manually, so I'm not a full newbie), and have used other Linux distributives before that also as a main system. Arch is fine, but unfortunately I recently realized that I need more stability and that's why I switched to Manjaro. I'm still not sure, but seems they do some tests and polishing taking Arch packages, making sure core components work well, etc.
PS I installed Manjaro not using GUI installer, since it doesn't support disk encryption well enough, and I don't use GRUB (default Manjaro boot loader), but refind.