Starting with the Parallel BZIP2 compression testing, Btrfs was not the fastest. In fact, at this test, Btrfs was the slowest. It took just 89 seconds to compress a 2GB file using PBZIP2 on an EXT4 file-system, but that quickly expanded to 106 seconds with Btrfs. Even the EXT3 file-system had required less time at 97 seconds and XFS just needed 91 seconds.
When compressing a 256MB file using LZMA compression, all four tested file-systems performed relatively the same.
While more CPU intensive than disk oriented, as a real world indicator, it took roughly the same amount of time no matter the file-system when encoding an audio file into an MP3 format using LAME.