I had the same question and here is what i found: The WD My Passport portable is the the shorter name for 2012 models(series: WDBxxxxxxxxxx) and are equiped with 500MB up to 2TB hard drives. The WD My Passport Essential SE is the name for the 2011 models (series: WDBACXxxxxxxx) and is available in a 500GB, 750GB and 1TB only. There doesn't seem to be any difference, as far as I can tell when you compare their web specs, other than that there is a "diagnostic utility" included with the newer model and that it has a slightly modified outward design. As far as I can tell, both the 2011 and 2012 models have 5400rpm spin rate drives, and both are available with USB 3.0/ USB 2.0. The faster 7200rpm versions are formated primarily for Mac, though I understand from some blog sites that they are not to difficut to reformat to PC NTFS but only transfers data via USB 2.0. So, to sum up, the 2011 My Passport Essential and the 2012 My Passport portables are basically the same, other than their outer appearance, and that the newest 2012 My Passport model is available in an impressive 2TB version. I hope this helps. ~ jano
PS. I joined this forum primarily to answer your question because I know how difficult it was for me to find out the differences, and I spent a lot of my time poking around to do so. I wish WD would be a lot more clear and up front about the differences(if any) on their product pages for these two portable models. I recently bought, and not yet recieved, a _ WD My Passport Essential SE _ thinking that it was the latest 2012 model, but I was relieved when I discoverd that the 2011 and the 2012 are different only by outward design and appearence-- their size and weight is nominal at best. My take on all of this is that WD released what seems to be new and improved versions when in fact all they really wanted is a way to market and introduce the 2TB version. I would like to hear what qualified individuals might have to say about all of this because I could be totally wrong. Again, I compared all the specs I could find, however there may be some other important differences that I might have missed or overlooked. At present, the new My Passport is a tad less expensive than last years My Passport Essential SE.
And I signed up just to thank you for your reply. Thank you! I spent loads of time and trawled through all the specs, PDFs, etc. too but couldn't figure out any difference except for the sizes. And this post turned up only in the second page of my Google search.