Okay, in the hope that this might help someone else I'm posting these results.
My first test had been using the Gigabyte SATA2 controller. So I powered off and plugged the Corsair Force3 into the Intel ICH10R controller, I also had my two WD 500GB HDD in Raid 0 plugged in there too. I had the BIOS set for RAID which I read somewhere also allows ACHI commands to reach non-raid devices.
So on reboot I had my Raid 0 and Corsair 3 and saw a huge improvement in performance:
Yeah, that looks pretty spot on for Sata2 with an SSD. My Force 3 drive didn't last long enough to actually determine if it degraded over time, and how badly. I would just use it, and by the time it gets slower Win8 will be out and you will be re-installing most likely anyway.