I bought a couple.
At the time they were part of my evolution but was pleased as punch to be able to go through the day and part of the next due to the 18650's. 18650's turned into the basis of most of my
vaping.
I still have them though the wife's ex husband is playing with one at the moment, complicated, as back up's. Can never have enough back up's lol
Anyway the plus point for me was not having to buy a charger as they can be charged via the Ego charger I had and you have already. That lasted about a week and I ended up buying one anyway.
Plus's - Compared to what you have they will seem to last for ever, no charger to have to consider.
Negatives - Regulated 3.4 as per a standard Ego battery so in comparison to even a 3.7 device pretty wane vape. Threads are not the best.
I would see if there is a Kgo alternative that you can use a Ego charger on and get that 3.7. I know it is only .4 volts but it makes a difference using low resistance carto.
Do I regret buying them ? Nope. They did me a great service at a fantastic price but with The Bolt out there for a few dollars more and retrospect being a 20/20 deal I should have gone for that. Depends on your budget really if the 18650 Mod is in yours and the alternatives are not go for it.