The published results aren't consistent with the general understanding that xz is faster than bzip2 while compressing better even at the lowest settings.

Xz beyond the lowest compression setting quickly enters the realm of diminishing returns, but when even the lowest setting compresses better than bzip2 and is faster in both compression and decompression, there is no reason to use bzip2.

The opencpu post completely ignores the compression setting dimension, presenting an incomplete picture. Xz is shown as consistently the slowest by a wide margin, even relative to bzip2. This is unexpected, xz will be faster in both compression and decompression than bzip2 when using a compression setting appropriate for comparison with bzip2 compression ratios.