Michael92, Welcome to ECF.
I don't know anything about the ePuffer but the prices on their site seem on the high side to me. What vendor were you considering using to purchase the
joyetech? To me, brand doesn't mean didley for anything made in China so I prefer to purchase Chinese manufactured goods from a supplier with a good reputation for customer service.
Joye brand (Vapor Kings)
Joye eGo TWIST
Joye 510 e-Cigarette
Not Joye brand (Vapor Beast)
510 Automatic Kit
Ego Twist Battery - 900 mAh
These models all have 510 threads which allow the greatest choice in extra goodies. There are numerous other excellent suppliers but I've done business with both Vapor Kings and Vapor Best. Both ship immediately and have excellent customer service.
The batteries for the cigarette form factor don't stay charged long and only last about 3 - 4 months. I find the form factor very comforting which helps reduce stress. However, the necessary frequent battery charging that is required is a serious annoyance.
The Twists have a cigar like form factor and the batteries will last while vaping much longer than the cig-alikes. The batteries generally die in somewhat less than a year. The variable voltage is very easy to use and quite helpful in finding a sweet spot that gives optimum vapor/taste/throat hit for any particular juice.
I have some cig-alikes as well as the Twists from Vapor Beast. I use both frequently so if budget allows you might want to consider purchasing both. If I were only able to have one form factor I would personally choose the Twist, hands down.
There are safety issues with any battery and all should be used according to directions. I would not be inclined to trust one Chinese manufactured battery over another, branded or not, as long as they are being carried by known reliable vendors. Using a battery charging bag will prevent serious charging disasters. Vapor Beast has a couple and there are others available if you Google "lipo charging bag". Don't allow your batteries to come in contact with metal which can be a problem if batteries are carried in a pocket, purse or gadget bag.