Depends if the drive is installed in a PC or the player/recorder. The player would probably just work with an RPC1 drive with no additional modification.
The people we've spoken to generally complained about the slow write speeds when used in a PC, and have cross flashed it to a GSA-4040B.
The region free versions of the GDA-4040B would work in the PC like any other. The RPC1 version would need DVD Genie, Region Killer, etc.