Though this topic is old enough, let me pick it up again.
I also encourage you to move the localization to Transifex.
From the view of translators, it is amazing that the translated strings are stored in translation memory, so in the case of an update a translator needn't start his job from scratch, but can leverage the already existing translations. Additionally, it supports team work, so multiple translators can apply for the translation of a project, adding reviewer privilege for the best translators, the quality assurance may be provided.
In the case of multiple languages, the challenge of "who is faster" may motivate your translators to complete a job as soon as possible - a kind of international competition.