The OontZ Ultra-Portable Wireless Bluetooth Speaker by Cambridge SoundWorks
The sound quality is good. The battery seems to last for days.  Bluetooth connection was easy with both my Android and iPhone 5.  Bluetooth immediately reconnects with my Android device, but wont automatically reconnect with the iPhone (IOS7).  On the iPhone, I always have to go to settings and tell the iPhone to connect again.  Trivial effort, but annoying.