we have a test instance with ez Studio LTS1.7.0 which is our testing system. We imported real customer content with ca. 4000 content objects. If needed we can provide SSH and webaccess to this instance. Backend credentials are the default ones.

1) We created test eZ instance on http://ezstudio.yoochoose.net:8000 and we imported a database with ca 4000 articles. Unfortunately after we triggered the export (see link below) we received only 25 Articles and not 4000.
http://ezstudio.yoochoose.net:8000/api/ezp/v2/ez_recommendation/v1/contenttypes/2/export?hidden=1&lang=eng-GB&fields=title,body,intro&webHook=https://admin.test.yoochoose.net/api/723/items&page_size=1000&transaction=20161219074311112
We tweaked the extension locally to avoid this restriction which led to point 2)

2) The current implementation is synchronous, memory intensive and creates high DB/system load which will cause a lot of trouble on customer systems. An approach to decouple it and minimize the load is to do this export job as an asynchronous task running in the background.
Currently the export is limited and it is not possible to export a big amount of content. On our test instance it was not possible to export more than 3000 items - if requested more we received an Internal Server error.