Over the years, I've had to deal with clusters of failures in pretty much every brand of drive. I've wound up concluding that all manufacturers at one time or another put out a line of turkeys.
Before I purchased a WD Green drive, I researched it pretty carefully. Now, this was in the summer of '10 and things change sometimes quickly in the hard drive industry, so what I learned then could be totally obsolete now. But what I found then was that the high-capacity green drives were holding up as well or better than most other series of high-capacity drives, when used as intended.
I also learned, and have observed for myself to be true, that the green drive is not intended for and does not serve well as a system drive. It has to do with how WD sets up the green drive to save power. Result is that the drive does OK in an environment where its role is to store and serve data (movies, photos, etc), but does not do well in an environment where it is intermittently but frequently busy, such as a system drive.
The green drive parks its head after just a few seconds of inactivity and the number of head parks that are available to a drive before wearout is finite. This proves to be a serious problem in Linux; the way that OS works, the green drive winds up parking its head several times a minute and can reach wearout levels in a matter of months if the drive is used as a system drive. It isn't as serious a problem with Windows, but is still a pretty serious issue.
I don't know the details of the failures OP or others have experienced with their green drives, but I do know they won't hold up if put in an environment where they are constantly parking/unparking the heads - in other words, where they are intermittently busy with dead times between activity measured in tens of seconds. They will work OK in an environment where they are constantly busy (no head parking) or where they are used for archival data or data that is served in large chunks at irregular but long intervals.
The green drive isn't a fast drive; slow platter speed which saves power. So, in an environment where it is constantly busy, most probably a faster drive would be a better choice.
Also, my experience is that the green drive runs quite cool. Mine is usually close to ambient temperature. This can be a problem in and of itself; drive failure rates shoot up if the drive operating temperatures are maintained below about 25C...and most homes will be below 25C much of the time.
I have mine positioned next to a busy 15K RPM SCSI drive which has the effect of raising its temperature a bit, which is good. Presently, I'm showing my room temp to be 21C, the green drive is reporting it is at 28C, and the SCSI drive next to it is at 34C. I try to keep my drives between 35 and 40C, which is evidently the "sweet spot" for reliability, but that's a bit hard to do...and I can't do it with the green drive. The SCSI drive most certainly is heating the green drive a bit.
So, my limited experience with them has been pretty good, but I do consider them to be limited in their uses. My research on them has turned up what I've described here. I wouldn't purchase one as a 'general purpose" or as a system drive.