Traditionally Memorex have taken their drives from Aopen, who in turn OEM Ricoh CD writers. I cannot be sure, but it is likely the Memorex is a modified Ricoh drive of some description.

There is really no such thing as a cheap and nasty CD Writer. None of the unknown brands of writers are really made by the Taiwanese company on the box, for example Aopen are Ricoh, Artec and Acer are Philips, etc. The only cheap Taiwanese company producing CDR drives at present I believe are Lite-On, and they're decent Clone-compatible drives anyway!

I am not aware of any 12-speed writers which are not Clone compatible in most respects. All the ones I've seen support DAO-RAW, and while a few might only support 16-byte subchannels I think if you are just backing up PC disks you should be OK.