Freelance software developer. Haskelling at night. Hopefully unconventional. Fan of Dvorak
Pacaur seems like the more feature filled AUR helper. It also seems much more active on it's github project page https://github.com/rmarquis/pacaur compared to yaourt https://github.com/archlinuxfr/yaourt.
The annoying thing about yaourt is those dam confirmation dialogs.
Also Pacaur is written in Python, as opposed to Bash. Which I think is a much more suitable language for a project of this size.
So my advice is go for Pacaur!
A even more feature filled AUR helper seems to be Aura. Though I guess it needs a bit more adoption. It is written using Haskell and supports some very cool features - rollbacks, deleting unneeded cache files and more - this readme page might be useful: https://github.com/aurapm/aura/blob/master/aura/README.md
I love Arch Linux!