Plextor has/had some problems with the latest SafeDisc 2 version with version number 2.51.021 found on for instance Medal of Honour: Allied Assault and Command & Conquer Renegade. But the Plextor seems to work very well with CloneCD 4’s AWS function and should now be able to copy these games just fine. Another disadvantage of the Plextor is that it cannot fully overburn to 99 minutes (it will fail at about 94 minutes) but no games or audio discs use this. The Plextor is recommended for dealing with audio protections which the Lite-On can’t cut. The Lite-On writer however can fully overburn and write SafeDisc 2.51 without CloneCD’s AWS.
Both drives are in my opinion excellent. Both drives support the reading and writing of the full SubChannel Data (PSX). The only other difference I know is that the Plextor 40x is picky with used media while the Lite-On 40x can write most media at the highest speed. The Plextor 40x writer is also limited to 24x recording when writing audio. The Lite-On’s are not.