Linux 3.3 Kernel: Btrfs vs. EXT4
Btrfs loses out to EXT4 on both the low-end HDD and high-end SSD systems with the stock mount options for each.
EXT4 also did better than Btrfs when running the NGINX web-server.
When running FS-Mark with 1000 files of 1MB size, the performance for the Core i3 330M HDD system came out to about the same speed between EXT4 and Btrfs while EXT4 won with the COre i7 720QM SSD system.
When running the same FS-Mark test again but not enforcing sync/fsync, EXT4 was slightly fast on the Core i3 nettop while the Core i7 laptop was slightly faster with Btrfs.