I'll add my 2 cents. Plextor is a great co. Thier customer service is excellent. In the past, they had the best performing burners. However, Lite-On beats them in performance and price now. It depends on what you want.
I have right now 2-40x Lite-Ons and 1-24x Plextor. Another postive thing about Plextor is thier resale value.