Compression default of v5?

[Froggie]

We will implement this feature as soon as possible, but there is no guarantee that it will be available in the next release.

Trying to determine if going to medium or high compression is worth the time or risk.

A tried and tested lossless method is used for all the DATA compression options... no risk is involved.

I would suggest testing it yourself to get the answers you require.  A warning... if using a modern CPU (4-cores or better) and having fast SSDs (NvME or SATA III) involved as a SOURCE and TARGET disk in the compression tests, you will most likely saturate your CPU capability as you raise your testing compression level.  If using an HDD in either position will easily throttle the CPU usage and not saturate your System.

Best to give it a try yourself...