Hmm. I use yaourt. "yaourt -S package_name" and it just installs what you want, period. "yaourt -Syua" updates everything, including your aur packages. I have something like 50 packages from aur installed, and I don't have any problems. Day-to-day, it has taken almost no effort on my part for the last 5 years. There were some big updates that took some care to do correctly (udev and filesystem come to mind), but most distros have things like that and arch's documentation is always great.