I'm an amature musician, but I think the accuracy is good, although you need to keep fresh batteries in the device for it to work well. If the batteries are going dead, it has trouble picking up sound. Also, I think the item is somewhat fragile (i.e. don't just "throw it in your music bag"). Otherwise, it works great. I like the readout - very clear to see whether your instrument is sharp or flat and what note you are playing.

Seems ok if theres no other noise going on. I bought one as a back up and when I tried to use it onstage and it was completely useless, picking up every nuance going on around me whereas I had no problems with other tuners, even mid song...