The sound quality is very good for bass, a little worse for acute to me.
The change of track or the volume is done by the same buttons. You have to press a few seconds for continuous changing track, pity it would be quicker.
As stated in the description, it is very strong yet very lightweight. It can be easily transported to a picnic without risk of breakage.
By being fully charged it lasts several hours. But with a phone that charges over USB, the battery discharges too quickly quickly.