It's been a while since last benchmarking any Linux file-systems on a USB 3.0 flash drive to see how the performance compares, given that F2FS and friends are being optimized for flash storage. However, off the Linux 4.2 kernel for kicks I've run some benchmarks on a 16GB USB flash drive the EXT4, Btrfs, XFS, and F2FS file-systems.
These are just some updated tests for file-systems off a flash drive and using native (non-FUSE) Linux file-systems for a low-end flash drive... I ended up buying four of these flash drives recently as part of a sale. They are the Lexar 16GB JumpDrive S33. The tests are being done just for reference and without a focus on the longevity of the drive's life, compatibility with other operating systems, and other factors that should be taken into account if trying to choose the best file-system for a USB flash drive.
Of course, curiosity got the best of me so at the moment I'm testing these four USB 3.0 flash drives together in a four-disk Btrfs RAID array... Those fun benchmarks will be published on Phoronix in the next couple of days.
All of the benchmarks were carried out via the Phoronix Test Suite benchmarking software and each file-system was mounted with its default mount options.