After dealing with both products, I came out with the following conclusion
FreeNAS is a great product for HOME. It can be installed in a very small machine, contains all protocols (CIFS,NFS,FTP,ISCSI) used by commercial products plus a media server and bittorrent. Basically,the FreeNAS media server allows you to stream music and video in your local network. so you can play them with any media server client (PS3,PC). It is not commercial supported.
OpenFiler is also a great product. It requires a machine with more RAM and disk space.It has all protocol used by commercial products however it lacks of media server and bittorrent.It is commercial supported. So I suggest you to go Openfiler for businesses.