which lithium battery brand is the 'best'?

[Lightbringer]

which lithium battery brand is the \'best\'?

I wanted to know which battery brand most people have had the best luck with? I hear a lot about sure fire brand, all the Inova's come with duracells, so I was curious. Also, is there any point to using a tester on a lithium battery? I thought lithiums where designed to give maximum voltage for the longest period....then drop off quickly. Doesnt a tester just test the voltage? Anyway, thanks for help