Forge version: 14.23.5.2768
Twilight Forest version: 3.8.807

While testing Block Hardness for mod compatibility, setting the compat block's hardness to 5.0F, much like what is set by default in BlockTFCompressed, appears to show that the compat's block mines slower. Further testing shows that setting the compat block's hardness to 1.0F then shows that the two blocks will break at the same speed.

This was tested with the same tools, which happens to be no tools.