Had this for about a week now. Had a bit of a problem when trying to send single files over 4Gb to it but that is because it is formatted with the FAT32 file system.
If you want to copy files over 4Gb to it, you need to do the following :
Open device manager
Find the memory stick under disk drives and open the properties for it.
Under the policies tab, change it to optimize for performance.
This will allow you to then format the drive as NTFS which allows files over 4gb. This is not a flaw with this drive but is the same for all USB drives over 4gb.
Once done I found the drive was very quick unless you started a few copies going at the same time which made it slow to a crawl. Apart from that great, especially at the price.