>No to all questions :-)
>I don't know hat is behind the hood but I suppose it is writen on C++, becuase you get only one DLL.
>I don't know what kind of algorithm they used in that library.
>I don't know if it is better, becuase I never used both of them. But I saw there is a compression level in that class when you compress files.
>It does not support encryption (or there is no point of that in documentation).

Thanks. I can only tell that it compresses better and creates a smaller zip file than winzip.