The 35A 2500mAh Efest is a solid do it all battery, but the margins on it are lower than the big brand name batteries and the ratings are unrealistic like all chinese vape specific batteries (you can't really use it at 35A).
We generally recommend to our shop customers to stock 3 batteries, one for each of these three markets. Some are also successful just carrying the first category:
General All Purpose Battery
The Samsung 25R is in my opinion the best general purpose battery and the one that I recommend if a shop is going to carry only one battery. This battery can work well in single battery mods from 20-75W, and dual battery mods from 30-150W. The Sony VTC5 is a very popular battery for this as well, although in my opinion it is not really much better than the 25R and is overpriced (and has very volatile price and availability at the moment). Some customers prefer it though so some shops stock both. Another very similar battery that some prefer is the LG HE2 which is also a very good battery.
3000mAh high drain battery for slightly lower power devices
Customers who want a long vape time and have single battery mods from 20-50W or dual battery mods from 30-100W are very happy with the 3000mAh LG HG2.
Cloud Chasers
Finally for the cloud chasers who have low resistance mechanical mods or high wattage mods 125W-200W there is the ultimate cloud chaser battery, the Sony VTC4.
Of course, particularly for the Sony batteries and to a lesser extent for the others it's very important that you have a extremely trustworthy and knowledgeable vendor. Sony batteries can't be bought direct from Sony for resale so testing has to be done and the counterfeits are getting better and better so that means the vendor has to be better at telling them apart. If you don't feel you have a vendor you can trust then Efest is nice because they have those counterfeit codes on there.
