I encourage everyone to go evaluate building and submitting a package using the AUR vs Launchpad (PPA). I worked at Canonical and would never go back to Dpkg. I recommend users try it out themselves and see how much easier and cleaner the PKGBUILD approach is.

AUR does have a process to rate, flag and comment on packages. It is also much easier to review the installation script using PKGBUILD. There are a lot of high quality packages in the AUR but you should review everything you install unofficially, just like installing packages from a PPA.