@Vapor
Superb job on collecting compression data and yes, it's based on 7Zip Fast compression ratio. (could be Fastest, will check)

Looking at my tests on the SF2 controller it couldn't keep up with the ratio that 7Zip Fast(est) produces, not sure how the SF1 handles vs the SF2.

For reference, I 7Zipped one of my VM's earlier today (Windows Server 2008 R2, SQL-Server, + some data) and it ended up being ~50% of the original size using 7Zip Fastest.
Still it took 40minutes to produce that file using an W3520@4GHz on an Adaptec 3805 hosting a 3R5 volume, there is no way that the SF controller is able to achieve that sort of compression (on the fly) as 40GB is written at a rate of ~100MB/s using a 60GB SF1 drive. (based on steady-state)
I'll do some more tests when I get a few more of the items off my to-do list.