Well as a lazy arch user i installed pacaur and just use official and AUR sources without much checking. It's just convenient that there's an AUR for everything
Also, as far as I know, pacaur is no longer maintained. I switched to trizen, which prints the PKGBUILD on screen before allowing the user to opt in to executing it. Not going to pretend that I always review the PKGBUILD thoroughly, but I do generally skim them, applying more scrutiny as packages become more obscure.
It's relatively common for people to be added as co-maintainers after posting even just one helpful comment (!) in an unpopular package, so it's worth double-checking to make sure a big change hasn't been made recently without the author's permission.