Anker def makes great batteries, I've bought other brands that just don't hold up like Anker does. I picked up a 20k one for $50, I've been using it for 2 years semi regularly and still good. My last Anker held up for 4 years before I lost it :(
I also have the JSAUX hard case with the rubber handle in the back fits perfect and can give it almost a full charge.
I have several, depends on the crowd.
Careless Whisper -George Michael, This Love -Maroon 5, Drops of Jupiter - Train, Someone Like You -Adele