I just received a Peterson Strobotuner 490ST a couple of days ago and just used it for the first time today. I have been tuning pianos for over 30 years and this tuner is a "dream"! I used it on a 5'8" grand piano and the stretch tuning set the temperament just the way I like it. It cut at least an hour off my regular tuning time and I'm looking forward to using it on different kinds of pianos. I am very particular in my tuning and I think this unit will remove a lot of my "stress" on getting the right sound. I have tuned the piano I tested this unit on many times and this particular piano sounded the best it's ever sounded. Very pleased!!