I've found (certainly in the cheaper bracket) that spending a little more on a good clearomiser gives the biggest improvement. The more expensive, generally the better pit together and better designed so you are less likely to get leaks and it will be easier to fill.
Also, replacing coils regularly provides more consistency.
The aerotank for example just feels like a nicely machined piece of kit. Everything fits together well and you can tell it will last. A great improvement on the T3S which, while it was good with fresh coils, felt a bit fragile and clumsyvin comparison.
I have no experience of fancy batteries so will leave that to the others
I've found (certainly in the cheaper bracket) that spending a little more on a good clearomiser gives the biggest improvement. The more expensive, generally the better pit together and better designed so you are less likely to get leaks and it will be easier to fill.
Also, replacing coils regularly provides more consistency.
The aerotank for example just feels like a nicely machined piece of kit. Everything fits together well and you can tell it will last. A great improvement on the T3S which, while it was good with fresh coils, felt a bit fragile and clumsyvin comparison.
I have no experience of fancy batteries so will leave that to the others