[url]http://www.archivesofnethys.com/FeatDisplay.aspx?ItemName=Share%20Spells[/url]
This feat (and to a lesser extent some of the others in the book with the same prerequisite) seem like they're potentially very strong for any inquisitor who's willing to dip a single level into nearly any pet class in order to qualify for them. Inquisitor's don't have the same selection of personal range spells that a wizard, or even a cleric do, but there's still plenty of spells that a less combat-focused inquisitor might really enjoy casting on the party beatstick.
(Alternately, this feat gives any full caster with a pet that's willing to take a three level dip into Inquisitor the main part of what makes a brown fur arcanist an incredibly strong buffer.)