LGs - GH22LS20 and GH22LS40

is there any difference anybody can tell me about?

NS/LS20, NS/LS30 Panasonic chipset
NS/LS40 Renesas chipset = better choice imho

AFAIK there are just GH22xP20 (PATA) and GH22xS30 (SATA), no GH22xS20 and no GH22xP30 drives.