Great tuner, seems to be accurate. I gave it 4 stars because it goes through batteries fast. One reason is the auto shut off only shuts off if there are no vibrations present for a few minutes. That's ok for playing at home, but not for live shows. There have been many times I've needed to tune between songs and the next song starts before I am completely satisfied with my tuning. The power button needs to be held down for a few seconds in order to turn it off. I don't always have those few seconds and the tuner stays on the entire time I'm playing. My last few tuners shut off every few minutes whether it senses vibrations or not. It may be annoying for home use, but I prefer that for live shows. I would give it 5 stars if the unit powered off after a few minutes, sensing vibrations or not, or if I had that option to select that feature.