IMHO, Plextor drives are way over-priced and way over-rated. You can buy a Liteon or Pioneer at very reasonable prices ($40 or less OEM/retail).
Plextors are "higher" priced but far from over-priced. You need to own one to make an authoritative judgment. I use Lite-On and NEC optical drives also and they do their job quite satisfactorily but the Plextors I own are more stable and reliable.