My expectations for this was pretty low, but it ended up sounding surprisingly decent, not incredible, but not bad. The build and materials of the device is sturdy, but cheap looking and feeling. Buttons and ports all seem a bit cheap, but nothing has broken yet. Bluetooth functions well, range is about average, battery life is good. It stays on fairly well if I do not move too much, but it will shift around a bit when on the rowing machine. Has USB C, that was surprising with such a cheap device. It has a few irritating flaws, it is always triggering the assistant on my tablet, because the assistant button on the device is the power button, so If the power button is held down to power off the device it will trigger the assistant first. Also putting a built in radio on a device like this is just stupid, it would have to have an antenna to even work and who uses a radio anymore anyway? Sometimes I accidentally press the mode button and get blasted by radio static. I never tried to use the SD card, so no comment on that. Overall I recommend it if you want to try out this style of device, it is surprisingly usable. It really made me want to try out the Bose, but I can't afford a $200 speaker right now.