A good review!
A little more to add to this :
The LG drives which use P-CAV for 16x burns are the ones with Renesas chipsets. Usually, a CAV 16x burn on an LG writer is a sure sign of a Panasonic chipset. The other give away is how Z-CLV for 8x DVD+/-R/+RW burns works : with Renesas the speed jump is from 6x to 8x. whereas Panasonic chipset shod writers jump from 4x to 8x.
I've been saying this for a while but this writer is the only Panasonic chipset writer which has good burn quality. Earlier scans posted in the forum here by owners of this drive showed similar results. It's quite amazing.
One question though : in the review you stated that the 4166B cannot do quality scans. How did you test for this? Did you just try to use Nero CD Speed to run a quality scan and get the usual "function is not supported" error message? I'm asking because CD Speed has a blacklist of brands of writers which it will not even attempt to try running a quality scan on, and LG is on that list. The blacklist is stored in the registry and so can be bypassed by modifying the registry. If you used CD speed to test and did not bypass this blacklist, the drive could be capable of doing quality scans but you would never know, because CD Speed would not really attempt to perform a quality scan.