I was being generous actually. These numbers are evidently worse than useless since they led you into believing that the Vertex3 has particularly good sequential write performance. Misleading data with no warnings is worse than no data at all. You can actually find single hard drives which are faster than the smaller Vertex3 in that respect. Common hard drives won't be but a pair can easily beat even the larger Vertex3. This shouldn't be surprising. You can learn about the performance of hard drives on lmgtfy.com. Then see Anandtech for background, tests and benchmarks about the actual (see above) performance of Sandforce drives.
OK, I guess you are saying that Storage Review uses compressible data while Anandtech does not: Quote AT:AS-SSD Incompressible Sequential Performance
The AS-SSD sequential benchmark uses incompressible data for all of its transfers. The result is a pretty big reduction in sequential write speed on SandForce based controllers.http://www.anandtech.com/show/4341/ocz-vertex-3-max-iops-patriot-wildfire-ssds-reviewed/7
So. ya, if you have incompressible data you do not benefit (again a guess since unlike apparently the many to whom the "benefits are well known", I do not know for sure, just using logic) if the controller does not strip out "empty space" in the file it slows the write down because it has to write most of the original file. But on the other hand if you do have compressible files, the SR stats should be OK. The why is not really important though since to me the end result is what is what's critical.
But lets forget that for now, and assume that no one in their right mind would consider using anything but incompressible file writes to characterize the performance of SSDs. The best SSDs seem to be in the range of 300MB/sec according to AT if I read their graphs correctly, and the Vertex 3 is 284.
Now look at HDD, fastest I saw on AT, the velociraptor. It shows 144MB/sec sequential writes. Assume best case scenario you can double this in RAID, and you do not beat by any margin the best SSD on uncompressible files sequential writes and barely beat the Vertex 3 unlike your statement to the contrary. You can add more drives to the RAID to get it faster at the expense of added noise and higher data risk. It also means that you need 3 velociraptors to get better than the best SSD, and then the $/GB AND total GBs are similar, as I just priced on Newegg.
3, possibly 4 of 7Krpm HDD in RAID possibly could keep up with the best single SSD, at a lower price and with more storage. But again at risk of storage failure much more frequent than a SSD. But this is more than a pair which you claim is faster.
Add to this that most files are probably at least a little compressible, and the fact that you do not double write rates with two drives, then two HDD NEVER beat a single large Vertex 3 SSD.
It would seem clear to me that HDD RAID is now really only of major benifit if you want tons of capacity. When I started this thread, this was not true, but since then SSD throughput has doubled.