I got one of these drives at the black friday sale. The one I got is a Lite-on. However, some other people who also bought the drive at the black friday sale reported that they got BTC drives. So, you might get either one. My guess is that digital research gets the drives from both manufacturers and repackages them and sells them as simply being a 16x10x40 CDRW drive with no guarantee as to who they will be manufactured by. So, which you get will likely depend on which brand they used in the particular batch of drives that the place you bought it from just happened to recieve.
As for IO magic, I believe I heard somewhere that they bought out digital research and now own their brand name. Anyway, with the drive I got the warranty registration card had IOmagics name and address on it. So, I would suspect that digital research is indeed now owned by or at least somehow affiliated with IO magic. Anyway, IO magic is alot like Digital research in that they sell repackaged products made by other manufacturers.