The card should be okay if you are only plugging in one device but your OCZ Vertex 3 will take a performance hit. If you plug in two devices there will be a major bottleneck and performance will be further reduced. The card is a PCI-e x1 card originally designed for use with a large capacity hard disk drive. If your motherboard has a PCI-e x4, x8, or x16 slot available you might want to consider a PCI-e x4 card. I have an Asus U3S6 PCI-e x4 add-in card plugged into a PCI-e x16 slot. It works for me but I can't recommend it 100% because it is not compatible with all motherboards. In addition it appears as if Asus has deactivated the card.
When it comes to affordable SATA III (6 Gb/s) add-in cards results are not that good. It is pretty much a crapshoot!
generally speaking, any 6G SSD will be stronger even on sata2 mobo's. The Marvell 6G controllers found on cheaper solutions will be limited to PCI-e x1 lane limitations even if the card is rated at 4x speeds. Only the Marvell 9182 which uses x2 lanes will be faster and is very limited right now with none that I know of being implemented on sata/raidcards at this point.
You can bet that the card makers will have to step up though as the SSD's are getting faster and faster now. This "is this card OK" is the number 1 question I see these days and you can bet they are watching and designing as we speak due to the huge number of people still running sata2 mobo's.
Just a matter of time until we have some cheaper add-in cards using Marvell 9182 chips capable of 600MB/s throughput with raids. Just saw a guy running 2 x 120GB Vertex3 drives off the Marvell 9182 from a G1 Sniper mobo and he's over 600MB/s. 9128 could barely hit 400+ with one 6G drive or 2 x 3G's. Probably be a few more months until they catch up, I guess.