I've got both, and while i've never done a comparision side by side, I can tell you that it's really no comparision to be made. the E41-B has extremely good resolution, smoother midrange, MUCH better treble, and weighs about twice as much. I'm pretty sure it's also got all air core inductors and high quality capcitors and resistors inside too. Even the bind posts feel high-end.
......And mind you... I'd be pretty happy with the E5Bi bookshelves in a small room. Very pleasant speakers.