If all your computers are using some versions of Microsoft Windows, then SMB is the way to go.
If you have any computers with UNIX variants (OS X, Linux ...), then you may need NFS for the following reason: SMB (Samba) has it's root in the DOS/FAT era, extended through the years to support longer names (LFN), but still it has limitations. For example, on OS X, you can have filename with '/' in the name, but this is not allowed in SMB. Therefore, if you have mixed OS X and Windows environment, the OS X folks who drop a file with a '/' in the name into a shared folder will cause havoc for the Windows folks. On the other hand, , SMB may play around with UNIX mode attributes to map the 'archive' bit which some Windows/DOS/FAT aware programs will look at. This will cause problems for the *NIX people.
However, be warned that the add-on NFS for DNS323 is an user-space implementation, which means, do not expect high performance or high stability. Also, due to the design assumptions at the time of creation, NFS is not secure file system, it is very easy to spoof somebody and gain access to NFSv2. You will need NFSv3 which is not available for DNS323, and since it uses Kerberos by design, it has export control restrictions.