The nice people on Crowdin have provided us with our very own server to manage our translations, and the feedback up until now is that the crowdin translation instance is easier to use, certainly for casual translators that come by once in a while for a few lines.

I have started the migration from Transifex to crowdin for all the translations in the different languages that we have, because it is a waste of time to do those translations from scratch every time. 

If you are curious, the ImpressCMS Crowdin project is available here : Impresscms · Crowdin