Buzz,
I understand your points, and agree that with two batteries in series, one will almost invariably discharge faster than the other. In fact, I would think it extremely unlikely that both batteries would ever reach the protection circuit cut-off point of full discharge at the same time.
And yes, I know that switching regulators are much more efficient than linear LDOs and extend battery life between charge. I have a switching regulator in my Big Daddy, but all my other VV boxes use linear chips. Since I own one, I know for sure that Shan Burkholder uses linear regulators in her VV boxes (the subject of the original post in this thread).
I also accept that some folks swear by AW high-drain IMRs and strongly recommend always using the best batteries money can buy. That's fine. In real life, we're always weighing the you-get-what-you-pay-for truism versus best-bang-for-your-buck necessity. In my own experience, however, I haven't noticed any significant improvement in charged runtime with the AWs, nor any particular loss of performance with Trustfires, at least the two types I mentioned to Miguel. As far as I recall, the 3.7V Trustfire 18650s and 14500s received good ratings in brand comparison tests from the engineering types at Lighthound (which surprised some people who had assumed they would do poorly), so I don't know if you include those Trustfires in your designation of "off-brand."
Basically, in Miguel's situation as he described it, I think a second set of batteries is an easy way to troubleshoot the problem, not to mention that at least one more pair would be a good thing to have. If he chooses to buy AWs, good for him. I was just trying to help him out with an inexpensive source if he wanted to go that route.
