The main advantage of burning at 16x or slower is, that the drive will burn at a constant linear speed (CLV) and produce a disc with lower jitter than burns performed at faster speeds. For data this is not important at all, but for audio it may be important depending on the player(s) the disc will be played in.
The NEC ND-4551A DVD burner is an outstanding CD-R burner when burning at 16x! The other drives in the series should be equal in this respect: NEC 3550, 3551, 4550
The 5S and 6S LiteOn DVD burners seem to be rather unimpressive CD-R burners, however. It's possible that LiteOn CD-RW burners are good, but don't even think of burning audio at 52x!