I have one of these coming next week. I ordered from Newegg on sale at $24. Comments on Newegg said that that the latest IHAS124-04 were the Optiarc 7240 drive. From what I could piece together is that the IHAS124 is a Sony/Optiarc AD-7240s with Lite-On firmware. Liggy has modified firmware for the IHAS124 if you are familiar with NEC chipset drives.
The 7240 do great quality burns on DVDs and are average readers. One of the better drive that are still in production. I have a Optiarc 7240 and wanted another one. The Lite-On was on sale for $5 less than the Optiarc, so I got the Lite-On. You can read about 7240's in the Optiarc section.