Hi,
I used jdownloads some years ago and it was perfect, i plan to use it again for a big dawnload portal but with all web technolgy evolution there are some usefull features like load balancing and remote host files, for examlle user can upload files to europe or asia server located according to servers availability or predifined configuration, downloads can follow same rule as we can host files today in many location (cloud) to protect data and to optimise data transfer. The are some doWnload php script can expand sotorage via webdav, sftp etc..
Sorry for my bad english.
Best regards