I have one of these 'Vantec NexStar LX - NST-475LX-BK' drive enclosures. It is a NAS device.
When I write a file to the device using eSata, or a SMB share I cannot write files over 4GB. I think this is because the drive is formatted with FAT32.
But when I access the device using FTP it doesn't matter. I can write files of any size. E.g. I wrote one on there last night which was 30GB.
Does this make any sense? Why? I guess the most important thing for me is data integrity.