I'll say that I have an NEC 3520, a BenQ 1620 and the Plextor 716a (0203, FW 104u).
When I am actually doing a burn to keep (family video), I only use the Plextor.
The others are fun to waste blanks with, comparing quality scores, burn times etc..., but when it comes down to making the best burns, the plextor always wins out.
This should be qualified by saying I find that almost without exception, all of the drives burn better without applying any "overspeeding", so I burn 8X discs at 8X. Thats the only speed of blank I use, and its the only speed that I burn with. Sure, sometimes some or any of the drives do pretty well with an 8X at 12, or even 16X (1620 on TYG02), but never better than the same media burned on the plex at "rated" speed.
8X burns take me 8:10. 16X burns take me 6:25. The small amount of extra time isn't important to me given the variability of the burns at high speeds (even on the plex).
The NEC is fun to play with, but has the worst burns, on any media (I use almost only -R, it does better with +R, Its true).
The BenQ is a nice drive for the most part - jury still out on latest firmware.
It is also much better on +R, but very good on some -R as well.
So theres another opinion, but I like the Plex for quality at "rated" speeds, the BQ for scanning, and also good burning, and the NEC is mainly used for reading -R discs into a authoring App (rips -R video at 16X).
That all said, I will say out of a stack of about 50 "test" burns I have made with these 3 burners, the Plex makes the prettiest quality scans, with the BQ a fairly close second, and the NEC firmly in last, BUT even the worst looking NEC scan plays without issue whatsoever on all my standalone players.
In a nutshell, they all "work" fine in almost all cases, but mostly people around here are alot more concerned with details that in most cases don't come into play with "real world" use (myself included).