I guess that's what makes the LB great -- user configurable so anyone can get what they want. Personally, I don't understand why anyone gets it with 9v, dual 9v, or AA's -- internal li-ion is the way to go!
The internal li-ion gives 12-14 hours of runtime at 48v phantom, or 25+ hours at the 20v phantom setting. Then it can be re-charged in something like an hour, or maybe and hour and a half. Even if I'm running at a festival, I don't record more than 14 hours a day and I can recharge at night. Or for me with Milabs that take 12-48v phantom and Beyer mc950s that can take 12-48v phantom, I can run for 25+ hours before needing a recharge.
It's all in your preferences and what you want out of your gear. Internal, rechargable, 12+ hours of runtime and potentially 25 hours, and the smallest case possible -- that's what I need.