file modification time:
there seems to be a difference how ftp and webdav deal with file modification time.
It seems there is a 'command' in ftp to preserve that time (several ftp clients and servers claim to do that), whereas webdav, if I remember correctly, can get the file modification date but can not set it on upload.
owncloud client and some propriatary webdav clients seem to have a workaround, but that works only in their software
depending on usage, that is a stong argument in favour of ftp. I don't want my files to have their modification date == upload date. After a later download, I would not be able to tell by date which version of the file I have.