Dave it just arrived Wed..haven't used it on stage yet..but works well in the studio...the battery specs states music playback up tp 35 hours...For sure it will last thru a gig..even though I am using bright screen and never turning off the display..

Video play and Internet is mentioned as 10 hours, I did not get this lenght of time, but as I mentioned I am hogging the power..

Yes it comes with a power supply,USB cable and ear buds..