Do you like the draw of the et-s tanks? I used those also for awhile. Or do you feel like the draw is too tight?
The reason I ask this is because if you are satisfied with these and they work for you, you may want the next purchase to be an adjustable voltage/wattage battery to make those tanks really shine! The aspire line has recently changed their coils, and can handle more power.
Maybe a Vision spinner or Innokin VV v3 so you can turn up the heat so to speak. It will give you the option to dial in your sweet spot.
When I used et-s tanks they had bottom dual coils ( bdc ) and now they have bottom vertical coils ( bvc ).
I was happy at 8 watts with the old coils and used the new coils at 11 watts and the flavor improved drastically!