Breezing Forms is certainly the best free alternative to GF and Formiable provided by the WP directory and just works as expected.
Previously, I've worked A LOT especially with Gravity Forms to meet my clients' requirements. But soon, I noticed that there was really no need for a highly expensive plugin and came across Breezing Forms.
One of the most stunnig features which finally convinced my to stick with BF was that everyone can use it to create unlimited variations of forms - without actually needing to know complex code.
I'd definitely recommend BF and encourage everyone to give it a shot.