An Android 2.x phone. Android 4.x+ replaced the MSD protocol they spoke with MTP which nobody seems to get right so you have FUSE filesystems like jmtpfs, mtpfs-simple etc to deal with your particular brand of breakage.
That was a pretty valid criticism about 2 years ago. I haven't really had any problems with MTP on Fedora or Ubuntu since about that time. Whatever gvfs is using for MTP works fine these days.
I sometimes plug my Android 4.x+ phone into a desktop with Ubuntu 14.04 LTS to copy some photos from the phone. It works fine, with no extra software or configuration required. On the graphical interface, it appears like a USB drive.