I've heard of Trustfire, but never a Tangsfire. If they are anywhere near the quality of the other "fire" brands (Trustfire, Ultrafire, Surefire), I'd be looking for something better.
For the 18350 size batteries, I recommend the AW IMR 18350 700mah. I've had much better luck with them than EFests, and AW IMR is the only brand I use now in all of my mods.
Batteries : AW IMR 18350 3.7V 700mAh
Not all batteries are created equal in quality, there is a marked difference between battery brands. I provide some helpful information in the below link. Panasonic is the leader in producing the top batteries, and AW tests and hand picks the best of those and rebrands them.
To learn a little more about mod batteries, study this guide that I made from my own research:
Battery Basics for Mods: IMR or Protected?