I've had some issues with nasty tasting vapor too. It seems to be caused by heating the atomizer to too high a temperature. I seem to get far more consistent results by drawing S L O W L Y rather than trying to drag like an analogue. On an auto battery I draw just enough to activate the bat and on an manual I draw as slowly as I can, but stop before I hit 5 - 6 seconds. It seems to make a big difference for me, but my story may be purely anecdotal.