1- It is not a user-friendly one. Difficult to understand some parts. UI could be integrated to the core Joomla.
2- There are 2 tables in DB and all records are stored mainly in the table jos_jf_content thus creating a huge number of raws for a single translation, say a menu item. In my case I have skipped some but I have 4 records for a menu item translation. I have not tried a content item buty it may be bigger than this. So this kind of approach will result in a huge db in no of records and size. This table can be splitted to a number of tables as it is in Joomla.