PRO:
I'm still learning the device, but "right out of the box" I used this on the Upright Stretch sweetener to tune an inexpensive 1970's upright piano. I've used a pocket chromatic tuner on several pianos previous to this with acceptable results, but this was waaaaaay easier to use. Cut tuning time in half. It locks on very fast, basically "real time," so I can get a reading at the part of the sound envelop I need.

If I can get it to show the 1/10 cents +/- for a given note I'll be even happier. I suspect there is a way.

The buyer experience was awesome, right down to the intro video on the website. Downloading software was a snap. The tuner cost less than my tuning wrench, so I can't complain there.

CON:
Unfortunately, using the mic, at least, it stops tuning (strobe disks turn off) too soon for the upper octaves, but I can at least get to C6, and I'll try the vibe pickup clipped somewhere next time, or an external mic, perhaps? The disks don't exactly "spin" like I would have suspected for a strobe tuner, which is a little disappointing. I'm still learning, but they don't seem that different from a needle type tuner, just clearer. I'd have liked more harmonic information like a real strobe tuner would give me...for only $4,000. Still, this tuner and my ear beat out the Entropy Tuner app and my ear by a long shot.

I also wish they had just put AA batteries in it. Now I have to think about yet another rechargeable battery. At least replacements are available from Peterson if it comes to that.