E2 is said to be less noisy (note that I have no experience with the E1 to back this up)
E2 allows you to switch modes (normal/tape/looper) by pressing both footswitches at once which the E1 doesn't
E2 is a pretty blue colour
AFAIK the recording time doesn't differ.
Both are cool and both are real-estate hogs. But so worth it. If you're a technophobe who wants to get into looping, the headrush is as simple as it gets. And it's a nice delay.
Steve