For the size, the B&O Play Beoplay P2 is an excellent-sounding portable Bluetooth speaker that can get quite loud and deliver a solid sense of bass depth. For the price, you might expect a stereo driver array, or simply larger drivers that deliver more bass depth and volume.
Touch-sensitive controls; Shake-based feature can be used to skip tracks or control other functions; Useful app allows you to customize EQ and controls
Mono audio only; Expensive for the size