1) about 7 hours runtime, phantom on, off 7.2 ah 6v. about 15 hours on a 12v, no kidding. I tested.
2) no mics sound real good straight into that thing, imo. The high end is a little muted, the midrange sort of blended, and the lows bloated and messy. But I think that flat fairly transparent mics like 480's or dpa 40xx probably sound best...the more color, the less I think you'll like it. Imo.
But running it line in is a whole 'nother story. I really do like it about as much as a 1k when run that way.