This is the device I use the most - it's a 2 GB device:

[1966731.544249] scsi 18:0:0:0: Direct-Access SanDisk Sansa Clip
2GB v02. PQ: 0 ANSI: 0


I just got a 4 GB device, and when I plugged it in, it wasn't
recognized. So I checked the device settings, and set the usb mode to
"msc", then plugged it in again and it came right up:

[1967048.305226] scsi 19:0:0:0: Direct-Access SanDisk Sansa Clip
4GB v02. PQ: 0 ANSI: 0

The sansa disk works on my home computers (ubuntu 9.10 and 10.04) and my
work computers (ubuntu 8.04 and 10.04) and hasn't ever given me any
trouble. I think once it corrupted itself and I just had it reformat
itself but other than that it just works.

My ipod OTOH is very finicky and I tend not to use it as much.