I assembled a few Intel compatible servers, mainly Asus motherboards, using LSI IDE Raid controllers.
http://www.lsilogic.com/products/raid_storage_adapters/index.htmlATA and Serial-ATA - They all work great!
Software RAID implemented on a few ASUS barebone AP140R using onboard ATA controller.
No problems with SW RAID implementation at all.
The Viatech IDE Raid chips on Asus boards do not have proper drivers under Linux. It's the same for Promise controllers.
Note about SMART:
Some "problems" detected/resolved when activated IDE S.M.A.R.T disk monitoring on ASUS barebone AP140R. I replaced the disks when indicated and it was ok.
But the NOT healthy reported disks ran fine on other IDE controllers (the LSI for instance), even with activated SMART also. So this might also be a controller specific issue and has nothing to do with the SW Raid under Linux.
Overall experience:
Serial-ATA IS faster than ATA but not much faster than ATA-133. Focus should be set on disk technology (RPM, cache) and stability anyway.
Better use RAID-5 with ATA-100/133 than RAID-1 with Serial-ATA.
Give enough RAM to the OS and implement SCSI-RAID, if throughput is important.
I use ICP-Vortex controllers for SCSI-RAID machines since years (the gdth Linux driver) - top products.