Zoo is one of the best CCK for Joomla, thanks to its power and thanks to Zoolingual. No Zoolingual Zoo is limited to monolingual websites. Zoolingual solves this problem in an elegant and easy for the user.
We have developed some websites with Zoo and really has no limits, whenever we think of how to solve any requirement Zoo has the answer. Sometimes you need the help of third-party extensions (Zoolanders, for example) but succeeds very well.
I have used the free version many times, I just buy the pro version to use with zoo and, as always, works perfectly. It is an extension useful and easy to use. Saves a lot of trouble with the "Itemid" menus.