Different Tailcap, black colour instead of natural HA, as far as the bezel on mine it throws a bit better than my normal e2e.
Check out
www.surefire.com for pics and all the feature differences.
If it is for pocket carry, I would lean you towards the e2e as the crenelated bezel on the e2d can be a hinderence. Just my experience, I bet there will be other opinions about this.
Also, if given a choice between my E2e, E2d, and L4, I would pick my L4 over the others every time. May not be as much 'throw' as the incandescents, but for me it has other features that make up for this (great spill, led etc). Just my opinion.
Hope that helps