I have a Black Silver Bullet as my main and love it. I have 2 atomizers, and 2 306 atomizers for testing. I am in the majority of my time a cartomizer user.
I have 2 batteries that I alternate day to day. Just ordered two more just in case. They pretty much last all day, in some cases two days. Just depends upon how much you use it. I bought the Silver Bullet specifically for the long battery time.
So much is self learning, but now I keep the regular atomizers for some juices , and the 306 atomizers for others. The regular atomizer burns normal (for comparison sake) and the 306 (low resistance) burns hotter. Some juices taste better with one or the other. A lot of personal opinion, and a LOT of testing of juices will lead you to knowing more.
My personal experience is that fruity flavors seem to do better on regular atomizers, and heavier, more tobacco flavors do better on Low Resistance (LR). There again, tastes may vary.
Same thing on Cartomizers. They Have regular cartos, Low resistance, Dual coil, and dual coil low resistance.
My Personal break down is, regular, warm, hot, and hotter.
If you like a mellow or sweet smoke, stick with regular atty or carto. If you like a good warm vapor or throat hit (cig), go with LR or Dual coil cartomizers.
Unfortunately juices vary soo much that this is not always the case. So keeping a small stash of each is a good idea for testing and daily purposes.
Of course someone will have an opposite view of this, so you have to just kinda soak up all the information, shop, try, test, an make up you own mind over time.
I will say though that the Silver Bullet as a main device is a great decision. I have a few other devices, but don't really use any of them anymore. I wish I had bought it first and skipped the tester models I bought. Would have saved myself a bundle.
Stricklin.