My iRiver E150 works nicely with Linux and *.ogg, but it doesn't do variable speed. You have to set the connection type to MSC instead of MTP. I like the first one so much that, when it needed replacement, I got a second one.
Sandisk media players, particularly the Clip and the Fuze, seem to be very popular among the Linux podcasters I listen to. Many of them also like to flash their players with
Rockbox; that's something I haven't tried.
This article from the Arch wiki might help:
https://wiki.archlinux.org/index.php...our_MP3_Player
