I guess it really all comes down to what's important to you really. Up until the release of the E01, I choose to EDC the Arc-AAA DS light. I did this for a reason. It had nothing to do with being in the "Arc Cult" or anything along those lines. The reason was that, even if I had no other lights source with me, I was guaranteed to have my trusty Arc on my possession. My reasons were not to impress anyone or to be able to light up a city block or anything else like that. It was to be sure that, in a very worse case scenario, I would be in immediate possession of a light that I could count for that had good run-time. It was to have a light on me that took a common cell, that had a really good chance of being available by others, in an emergency situation. My reasoning for all of this really solidified during the 911 disaster. Does anyone realize how my people didn't make it for the simple reason they could not see the way out? Although I've always been obsessive about having some sort of light source with me at all times, 911 increased that possession.
So, here comes the E01. A light that not only runs longer on that same little, easy to find alkaline cell, but it runs at a much better level of regulation. Even more importantly to me is that the E01 will fire (start and produce light), from a cell that would be considered long drained by any other application. Go find yourself an alkaline battery, drain it down to .4 volts and tell me of anything that it will successfully power. Let me know how you make out. Only time will tell the reliability of the E01, but I'm banking on it to hold up to whatever the circumstances will throw at it. It has to, since my life and lives of others may depend on it.