My SanDisk Mini Cruzer works fine on both my laptop and desktop with SuSE 9.0, but RedHat 9, RedHat Professional 3, and Fedora Core 1 refuse to recognise it.
My 6 in 1 card reader woks fine in all the above redhat/fedora versions. I agree the thumbdrives can be very finicky. Particularly the MiniCruzer, a google search reveals allot of folks having problems with it in linux. I guess I'm just lucky it works well in SuSE.