I have projects in Transifex (tx). Translation workflow is different than GetLocalization. First at all, tx is hierarchy - you have lead of project, coordinator of translation team, reviewer and translator roles. There is no voting system, only suggestions. Tx has translation memory, glossary and history of translation.
One most best parts of tx is API and console tx-client that relies on it. You can even rollback and mass-import in that client.
Tx used by Fedora as platform for entire translation efforts for that distributive. XFCE uses own (pretty outdated 0.8 ) instance.