I've been playing guitar for 59 years and have never been able to accurately tune my guitar. I've played professionally on stage and in the studio and have have owned several tuners that got the job done most of the way. Then I would use my ears to get it as close as possible. It became an acceptable nuisance. A few months back I learned about James Taylor's tuning method and got a clip on tuner that displayed cents so I could approach that sweetening style, and it was an improvement, but it was always difficult to have it land on the exact cents. Then I stumbled upon Peterson tuners in a review for another tuner. I had heard of them but had never owned one. So upon researching, I ended up buying this wonderful little tuner from heaven. I mean, really how exited can you get about a tuner? Evidently, VERY excited. I was surprised that they offered sweetened presets. How brilliant! It was exactly what I was looking for. I did a Facebook live solo acoustic show the other night using the acoustic sweetener, ACU preset and was so delighted that my guitar sounded and stayed so in tune! I didn't have to retune when I used the capo or took it off. It actually improved my confidence and performance. What a huge relief! BTW, I've heard that the James Taylor preset inspired Peterson's ACU preset but they do differ a bit. But after downloading the JTG preset from Peterson's website, and comparing, I personally prefer the ACU preset now. I also rehearsed with my duo partner and tuned both of our guitars with the ACU preset and voila, you can't beat the sound of two acoustics in tune with each other. So now my partner is getting one also. Like others have said, it takes a subtle touch to get the strobe to stop moving (as much as possible) but I've already learned and it's super easy. I tune much faster in fact now. Thank you Peterson for creating such an amazing useful tool!!!