I can't comment specifically about "iHAS W" drives since I don't have one. (Nor do I have any easy access to one).
I don't do any burning at all these days. So I have very little to say on this particular issue.
But I do a lot of dvd extraction. If you're like me, speed (and accuracy) is the primary issue when it comes to computer dvd drives.
I recently purchased an "iHAS-124 FU" and also an Asus rebadge of this same F model, where I updated both units to the CL08 firmware (linked from this forum).
Even with the CL08 firmware updates, there are still some slight issues with my iHAS-124 F (and Asus rebadge) going to full speed when a disc is first inserted and read by the drive. I made a post on this and found a partial solution to this problem:
(In contrast, my older "iHAS124 E" drive didn't have this problem).