my two cents on this, The LiteOn 1633s was a big disappointment for me, remember though that this is anecdotal evidence only, but I had to send it in a total of 4 times by which time they didn't have it in stock anymore. Each time they sent me a new one. The latest one survived about 110 burns before it died. The previous ones didn't survive even that long. From what I hear the 1633s and 1653s where pretty good compared to the 1693s. So that should give you a note of caution on that. BUT the 1673s seems to have a pretty good track record right now, which makes me wonder if the quality control of LiteOn was better with the 1673s over the newer but supposedly same hardware of the 1693s. I suspect the 1693s is an evolution of the 1673s in engineering, where they took some shortcuts to lower the price of production. This usually means a less robust product.
I am also looking at new DVD burners at this time and have settled on one of the following 3:
BenQ DW1620 PRO
In all cases I am going retail since it is about 55 or less US dollars in cost. BUT the OEM versions are about 5 to 13 dollars lower so... if you don't need the software then that is the way to go.