Pros: I bought this drive in 2008 when good SSDs were $7/GB. It has been flawless in that time, and was always very responsive. It also never developed any of the strange clicking sounds I've heard on WD's Green series and certain model Seagate drives.
Summary: I bought this HDD because I’m finally getting around to putting Win7 this machine as I have some of my others (vista is getting phased out as ME did and XP finally did). This computer had (well still has) the bigger WD6400AAKS as the sole HDD. The 640GB one is going on 5 years old now and has gotten hours of use on an almost daily basis.