Pretty new to this stuff, myself. I had a writer for four years but it was an HP 4x2x20 unit. I never cared what technology it used as long as it was reliable writing my data backups. It was (as long a I avoided blue dye media).
When I decided to upgrade I was basically waiting for Liteons to come down in price. I almost purchased a 24x10x40 unit a few months ago but while I was deciding the price went up from $70 to $90 (at Newegg) so I waited some more. Finally, I saw the Cyberdrive 36x for $71 (w/ free shipping). I quickly read a few reviews and decided it was good enough for my needs. Had a software incompatibility which was fixed with an InCD update. Now I'm happy.
I don't know what P-CAV and Z-CAV are but CAV stands for Constant Angular Velocity which means the drive maintains a constant spinrate even as the laser moves from inner to outer portions of a disc.
I have heard of Z-CLV which is Zone Constant <b>Linear</b> velocity. The way I understand this (and I may be wrong), going from the inner portion of a disc to the out portion there are different zones (usually 4, 5 or 6 zones). Within each of these zones writing is done at a constant rate, a lower rate at the inner portion of the disc inceasing in each successive zone to the outer portion where the drive's maximum speed is reached.
As for various drives showing up at CompUSA, only CompUSA will know this. I personally don't actually recall ever seeing Mitsumi drives in the USA. However, Mitsumi drives use ExacLink underrun protection and so do Cyberdrive units. Maybe a conclusion can be made from this, maybe not.
I've not seen Liteon drives in retail stores in my area but I have seen Cendyne drives. These are rebadged Liteons (or least they have been for the Lightning I, II, and III models).
<b>I have so many cookies I now have a FAT problem!</b>