Deltas, USAs, BTCs are (like some have said) loud and sometimes unreliable. I've had a run-in with a Delta B4. Didn't read some VCDs and a couple of Software CDs. BTCs were just loud on access and access times were abysmal and the CD access light being on when a CD was inside the drive annoyed me.
Cheap, gets the job done, but don't expect performance like say a Toshiba, a Sony, a Pioneer, a Teac, et al drive (no particular order 😛).
Aopen, I've heard, are lower-end Pioneers but that's what I've heard somewhere. **Don't know the validity of that.**