I have a few of the LSI MegaRAID i4 cards and have tested them using a few old Maxtor drives, the performance was good, not great, but good in RAID0. I will add a link later to the performance run of diskwriggler with the configuration. If you like I will part with a card or two for real cheap.
So here is the link to a capture of the run of one of the LSI cards running in RAID0 with 3 of the 120GB Maxtor ATA drives. These are old drives with little cache and slow rotation speeds. The drives were on different channels each, though another test showed little difference in writes or reads with 2 drives on one channel. The interface on the controller is 100MB/sec ATA.
Still not bad performance considering. I would be interested in the performance of one with a few of the more modern ATA drives at 7200RPM and large cache.
Mike