If you would have read the forum you would have known that many of us are using drives with their own power supply, and/or drives plugged into powered hubs. I've used all of the above scenarios. WD admitted to me that their is a known problem with macs stepping down USB 3 to USB 2 and sometimes having power and connectivity issues with these drives.
An upadate on my situation: Western Digital sent me a USB 2.0 cable, which was half of their super speed 3.0 cable (USB micro B to USB). This cable seemed to fix my self eject problems with the drive, BUT... then the drive failed on me. Figuring my data was more important than the cost of the drive, I jacked open the enclosure and removed the drive. What I found in my case was that the USB controller board that's screwed into the drive as part of the WD enclosure had partially burnt up. Further more, there was heat dispersing sticky tape applied to the controller board. When I took it to a computer electronics shop they said that's what they do when the board isn't passing testing properly but is still considered 'saleable'. So WD had a cheap controller board in the enclosure that was basically a faulty yet salvageable board. I purchased a new enclosure and slid the WD caviar drive into it. Unfortunately what I did not know was that these My Book Essential drives are encrypted by a special WD encryption algorhythm, and that the data is basically unrecoverable. Luckily I had the data backed up in many other places although it took me a long time to pull it all back together. The drive has since been reformatted and is working like a charm.
Long story short, I think I'll be putting together my own enclosure/drive combo's in the future. As I understand it WD takes this $100 drive and puts it in a $9 case, and many of these enclosures create the problems rather than the drives themselves. I've had too many drives go bad that probably started with or were entirely related to cheap enclosure problems.
Good luck to everybody out there. My best guess is that many of you are having these USB 3 to USB 2 step down issues. No one has really addressed these issues directly yet and it's probably not likely to happen as Apple looks towards USB 3 integration in their next series of hardware releases. If you're at all electronics comfortable and can back up your drives I'd go get a new specifically USB 2 enclosure at a micro center or some such and liberate your drive. I'll continue to watch this thread for updates as I still want to understand these problems better.