I am shopping for a new tuner and I have decided on 3 that seem to be in the same price range, the Boss TU12 and TU12H and the Korg GT12. I have a couple of questions about them: 1. What are the differences between the Boss TU12 and the TU12H? Which one is better for notes like low B? 2. Which of the three tuners is the most accurate? 3. Which works the best for notes like low B?