As I mentioned earlier, HDTach is not the best benchmark to run for RAID arrays. Some configurations provide results as expected, others don't.
Did you find the performance for the RAID 0 on the 3Ware felt comparable to the Marvell?
I'd be inclined to run the Winbench Disk Inspection Test on the 3Ware RAID 0 and see what results you get. We know RAID 5 didn't work well (for whatever reason) on the 3Ware, but at this point we only have HDTach results for RAID 0 which, to be honest, don't count.
With the 3ware I felt that the system was lazy and not too responsive...
I didn't do accurate tests, but I had this feeling.
Anyway, I sold all my Raptors because of the fact I was not using them at their full potential, and replaced them with 4 Seagate Barracuda 7200.7 80Gb, made a RAID 5 Array, and this are the results (red) compared with my Raptors (blue):
They are even slower...
One thing is for sure, no more 3ware/AMCC inside my case!!