If you must get a Fenix light, then get the LD01. You can run it like an E01 on low. Of course, the beam is much better and multi modes makes it a much better light. With something like the LD01 (again if you must get a Fenix light) you have one light that can be used on low for long battery life, and on medium and high for REAL work. And you only have to carry one light. I bought an E01 and returned it after a week. And that's was a year ago when choices for single AAA lights were very limited. Now with so many great choices available, I don't even have to consider dim, one-mode, limited use lights.
BTW, all the lights I have ever bought have never failed me including the returned Fenix E01 (except when the battery is really low; but then that's battery not the light). The point is don't people get tired of saying "this light has never failed me"?