look, if you browse the CD-R/W forum you'll find plenty of posts discussing the question of which of the 2 drives is better.
since this would take some time, i can't be bothered to look for them for you. do the searching. read the posts.
[apart from looking for topics titled "which is the best drive to get?" etc., it might help you when searching to look for posts by rdgrimes, he does a lot of testing and posts a LOT of info about burn quality...very good. also, if you're looking for posts of Plextor Premium vs. Lite-On 52327S look for aviationwiz, he's head of the Plextor pack, and in dozens of topics where the question came up "what drive to buy" etc. he started the old debate by saying "Plextor is the best". these few search keys should keep you busy for a while.
if you want you can look at www.cdfreaks.com
too, they have a database of reports of burns, speeds quality etc. (i don't know much about it, i think it's rather new) so you might find more relevant info there.]
personally (if it's of any interest to you):
i would get the Lite-On 52327S, for use with KProbe. but for me money is also a consideration.
if i already had a Lite-On drive (any drive, not necessarily the 52327S, for KProbe) and money wasn't an issue i would probably buy the Plextor Premium, and i have to admit that part of the reason at least is a personal preference, i have a liking for Plextor (and i know it's irrational and not based on any hard facts. not that there aren't facts to support it, but i do
know it's irrational).
that's just me. i don't know how much this info will help you out. and unless you have a more concrete question than "which drive to get" i don't think i'll add anything more. maybe someone else will come along and voice his opinion or point out facts which i've missed (or gotten wrong?). but then again this is a very tired and chewed-up debate and i'm sure i'm not the only one weary of it.
good luck, and i hope i've been of some help.