Peterson's strobe tuners have for years set the standard for accuracy by which all other tuners are judged. Nearly every self-respecting repair shop I've ever visited has a Peterson on its bench, and I've seen their portable tuners on numerous stages. They've lately moved away from big, lab-sized tuners, and more toward tuners that are usable onstage by anyone. It's a welcome change, and your guitar will never be more in tune than it is with Peterson.