If I am not mistaken, for you to take full advantage of the speed of the intel, you will need SATA-III which the 6 x 3.33 does not have and I have not heard of people having very good luck with an SSD as an external boot either using the PCI slot to be able to fully realize SATA-III speeds.
I have the OWC in my 6 x 3.33 and cold boots are between 15-17 seconds, pretty darn fast. I also put it in my second optical bay slot so I can have all 4 regular bays open for storage.
The OWC also touts "Block Management & Wear Leveling". Perhaps with OSX Lion we will get to take advantage of Trim support which both drives would be able to do.
Someone feel free to come in and correct me if I am wrong..🙂