Atomizers are a crap shoot in my opinion .. I had one that was used daily for 5 months that finally died .. I had at least two dead out of the box ... I have also had a few that were weak or the flavor that they shipped with simply could not be overcome. In the end, I figure typically 60 days for a well performing atomizers, all said and done.
As far as the eGo batteries ... I still have my two originals which each will last 7 or so hours per charge under casual vaping practices. Not nearly the randomness of atomizers ...