I've got a SiD. I picked up a nitecore i4 from Amazon with two efest imr 2000mAh high drain batteries (flat top). I soon bought two more batteries... It's nice to have some charged, and not to always have the charger running.
I get about a day out of the 2000mAhs. I'm a pretty heavy vaper though. I rebuild 1.3-1.6 ohm micro coils, at around 8 watts. I haven't been dual coiling... Yet! =) The batteries take several hours to charge. If you are charging unattended people recommend getting a charging bag to put the charger in. I don't have one, but thought I would mention it.
My sid pin did start shorting like I previous poster said, I added a blog entry with the fix. Vamo also has the same problem. That said, I'm still really happy with my sid.
I paid 35 or so for mine, but msrp seems to be about 60.
Good luck and I hope you are happy with your purchase when you make it!
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