I have two packers and they are both 3.5" Mr. Limpy.
I got my first one from Early to Bed. It held up really well but somehow I gouged out a piece of the side. The hole in it got bigger and bigger until I felt uncomfortable wearing it anymore.
I ordered a new one from the Levamentum Project because it was cheap, even cheaper than usual. Despite it being the same product, my new one is bigger. It's the same length, but everything about it is beefed up in comparison to the first one. Thicker, deeper, etc.
I never really understood when people complained about the Mr. Limpy attracting lint and sticking out like a boner all the time. My old one didn't do that, at least to the extent people claimed it did. But the bigger one sure does. It's softer, way stickier, and picks up lint like nobody's business (heh). It's also much harder to wrangle into the pants without it making a huge bulge.
So my question is... why the difference? They must have made two versions of the packer, and the one I first got has to be the "second wave" because it's so superior. But maybe online stores aren't stocking the same one, so that's why there's a divide between people who love the Mr. Limpy and hate it.
Picture comparison, excuse the crappy webcam:
http://i1130.photobucket.com/albums/m522/phoenixflorida/Snapshot_20121031_14.jpg