My main PC has both of the drives you mention, a Benq 1620 and a Nec 2500. My secondary PC has (at the present moment) a Nec 3520 and a Benq 1620. On the shelf are an LG 4163, A Liteon 1213@1653, and a Pioneer 108.
The Nec 2500 has a permanent space in my computer due to how well it works with cheap media. I have two Benq 1620 burners, one in each computer, because they are the best drives, overall, in my opinion.