Of modern Flash MP3 players, which one of them has the fastest throughput when syncing, or just writing files to it?

I have an iAudio/Cowon G3 player, and I love it's tiny form factor and features, but it's syncing/uploading seems pretty slow.

Am I just seeing the limitations of a USB2 connection, do some players have a better, faster USB2 implementation and faster writing to the flash than others? I mean, if they can run a hard disk reasonably quickly of a USB2 connection, they should be able to have a similarly speedy interface to an MP3 player, don't you think?

Can anyone recommend devices that are very fast to do file transfers?

- Tim