Sorry Ryan I edited my post today. It was lengthy and provided a good explanation but in my haste to reply and get out the door there was an important omission. That is why you see the post you see as an edited version.
Since the FAQ many things have surfaced wrt batteries etc... that is how quick this world we live in evolves. The FAQ is pretty much accurate but could improve. That is why many had the idea of a FAQ but never launched one. Not that the data is innacurate or incomplete, but it was meant for a beginner visiting Isaac's site and not a compendium of where we are today.
If I have a better understanding wrt batteries today compared to when I wrote the FAQ, it is because of the interactions an exchange of information with many members here and the rest of the forum. The FAQ was a compendium of the known facts and discussions that took place at the time.
It is also to be understood that I prefer "protected" batts over safer chemistry, even Battery U recommends this. At the same time, a PCB is prone to fail just like any other electronic component. My inaccuracy in my reply this am did not come from inaccurate information but rather incomplete information, to wit: using the proper atomizer with the batteries used. Now since folks do not do this, then the recommendation supports the IMR because they will withstand the torture us vapers put them through. That is a responsible answer IMO.
Some vapers go after heat at all cost (wattage) other target a specific region of said wattage (me) and will adjust batteries and atomizers accordingly, to not only suit a particular vaping style but use the batteries for maximum efficiency. I use Isaac's 5.2 atties at 6 volts. Why? It puts me bang on at around 7 watts, but yet the atty is only consuming 1.15A. In a regulated VV device this is pure bliss and something the RCR 123s are capable of delivering. All bets are off if I was to introduce a 3 or 3.5Ohm atty into the equation which is looking for a 2-1.7A power supply.
Yes I have a knowledge of batteries in general. But it doesn't stop there IMO. Hence my reply IMRs all the way because they cover the largest spectrum for the average vaper.
In closing mAh is not the be all and end all when it comes to batteries, nor is watts the be all and end all towards vaping satisfaction. Finding the sweet spot and achieving that sweet spot with the proper atty/battery combo is, IMHO. Then when looks at battery performance time ... I hope this make sense and helps.