I possde for over 2 years and has not moved I just changed the battery a few times but he eats too much. It Ragit well, but it's not the top, but good about 15 (me is the seller of my first guitar that offered it to me!) Is expected not something foolproof .. . it can be used for an acoustic (There's a microphone), an electric or electro, you just plug it into the guitar and the amp (input & output) also very practical.
I have all of the same opt for another tuner, a little more efficient and more reliable: a Korg DT-10 in the form of pedals! is a real treat!

I put 8 / 10 because it is never perfect, because ... There's better as a tuner For my part the Korg DT-10! (Even though I know it's not the same price)