Here is a question to ponder. Why does using FlashFXP upload files much faster to the xbox, than using FileZilla? What settings do I need to change in FileZilla to make it upload faster? If using Filezilla, it will easily take over 5 mins, whereas flasfxp can upload the same movie file in about 3 mins or less. All of this is done with default settings. I think there might be a setting change needed with filezilla, but not sure even where to begin.
It's all I've ever used and haven't ran into any issues with the FileZilla Client. Maybe check your firewall rules? EDIT: All my settings are default. Are you using a beta release?