Great review. This is a very important issue for some people. For me, I don't like getting the most expensive new edge tech when I can get less expensive options. RAID is a very simple technology, but it happens to work better because like all things, more heads do better than one in a thinking contest.
I would have been really impressed if you guys took 4 drives at 7200rpm and low sizes, like 80gig drives, and did a RAID 0 with 4 drives and compared that speed with them. The access time would have been the same, but for the cost, the read and write would have been retarded high and made it look silly.
Then again, your electricity bill may be the difference in the cost, lol.