Just to stir the pot a bit in the long debate; is the Peterson worth it? I didn't answer the question for you but I've come close to a determination in my own mind after borrowing tuners last week. Here they are and some results (ymmv); Methodology; Retuned the guitar for each tuner and then matched them with the other three and my own ears. For example; Tuned up with the Seiko and then compared (without retuning) what the other three measured and how each sounded. Seiko ST727 Seiko vs Strobo; Surprise! Low E, A and D when tuned matched perfectly with the Strobostomp. However, the G string seemed to always come up a bit flat. The high E and B strings were a bit off as well (generally tuned slightly flat). Seiko vs. Boss; the Boss couldnt read a difference between the tunings on average. The Boss generally said the E was sharp though. Seiko vs. Korg; G string read a flat on the Korg. Boss TU2 Boss vs Seiko; after a few iterations the Seiko generally read the boss was flat on the low E and G strings. Boss vs. Strobostomp; the largest difference as I could tell. Each iteration returned something different from the Boss, for example the low E sharp then slightly flat. Very hit and miss. Boss vs. Korg; on par, the Korg measured some differences on each iteration flat and sharp. The E string still giving troubles. Korg DT10 Korg vs. Seiko; Seiko came up in tune. Korg vs. Boss; Boss came up in tune, no measurable differences. Korg vs. Strobostomp; Generally high E slightly flat, G very close Low strings tracked well. Peterson Strobostomp (guitar tempered setting) in short, each of the other three found the Peterson to ring up green and perfect the first time. No differences on their readings. Now, my overall thoughts about how long it took to tune and how sweet it sounded; Seiko ST727 Great bang for your buck, pretty quick tune. If you tune twice through from a complete retune chords sounded sweet with very little noticeable dissidence. In a jam/stage session this would work for me. Slight tweaks on the G string were generally required. Boss TU2 Never thought the low E and A stings sounded right. Overall it didnt work for me out of the four. I would (and was) constantly be retuning by ear. Korg DT10 Dig this tuner, sounded good, tracked well. Chords sounded clear and matched; would be my choice for stage/jam use on moderate budget. Strobostomp Chords always sounded clear; never thought to go back and retune. Sometimes it took awhile to track the B and high E. I would think twice about recording without one. In a jam session at least you know it wouldnt be you out of tune. Disclaimer I dont assume this is a scientific process. Just some musicians curious about how much better certain products are from others (and invariably the cost differential) in their own minds. It helped me decide what I needed in life and thought I would share for those on the cusp. If you must flame away, please, go easy.