Its not that they are faulty it is just some drives are better at some things than others.
Like for example the NEC's and Benq's are the best burners you can get. Sony's are practically useless compared to both of those two. But you couldnt really say sony drives are faulty.
Same with rippers. Some drives are better at ripping through CRC containing disks. Some are very fast rippers and so forth.
The Aopen 1648/AAP was generally known as the crem de la crem of drives as it was a good ripper with amazing speed. But you cant get it no more.
The Asus 616A was also producing coments of amazing ripping so i took the plunge and ordered one in SVP's sale. And it was the best move i ever made. Which is why i am raving about it.
The second best move i ever made was at the same time i bought a Benq 1650 burner which is the best burner i have ever tried. So i am pretty much sorted now on both ends.