Recs.
Updated
Pacaur is an AUR helper that uses cower as its back-end. It's aimed at advanced users who want to automate repetitive tasks.
Specs
Pros
Pro Same great search as cower
As pacaur is built on top of cower, it has the same very powerful search functionality.
Though since pulling the PKGBUILD and the install files from the AUR server is done by pacaur itself, it is still able to perform a small set of actions if cower fails. (This case is important on an pacman database update which requieres cower to be recompiled. Since pacaur is able to fetch and rebuild cower without using cower, it is quite easy to do so.)
Cons
Con Aborts on building packages if an out-of-date .SRCINFO pkgver is detected
Despite having mechanisms for ignoring .SRCINFO for VCS packages (or simply regenerating it once the user has trusted the build files), the developer claims this is a feature, not a bug, and that pacaur is, quote "Inciting maintainers to update" at the expense of users being unable to build the package at all.