All the mentioned Peterson tuners have that same accuracy, as do the TC tuners. I was very careful to pick tuners that do as it’s kinda important when intonating a guitar.
While Fractal doesn’t specifically state their tuner accuracy, it’s pretty easy to test whether their accuracy is in the same range by tuning with the built-in strobe tuner while one of the others is in-line and see if they match. Or we can take the tuning fork output of the StroboPLUS HD and run that into the input of the modeler and see whether it matches.
On my FM9 the strobe display is quite steady. If it's having problems because of EMI or old strings, I can switch to the neck pickup, and if that's not enough I'll roll off the tone-control to get rid of upper harmonics.
Previously, my choice was a Korg Pitchblack tuner, and it was pretty good, but didn't have the pin-point accuracy of the 0.1 cent tuning ability.
So for the time, like others who prefer more accurate tuning, I used the FM9's tuner for tuning my guitars, but the Korg for intonating or changing strings.
And this may be the issue with my guitars...because I usually don't practice each week (unthinkable!) the strings may sit for a time and absorb oils from cooking or just age and tarnish from being on display. If the strings age, well, they're not being used, but they will still age and lose some of that "new string" resonance or harmonics.
I guess that the answer is you gotta keep putting strings on guitars if you want something to work better with your tuner. I think that if you give your guitars a chance with new strings, they'll put out a better signal that your tuner can read.
It's like when your kid asks for his allowance; you give him a job to do, like putting out the recycle bin, and both of you are happier because the kid did what he was asked and the kid receives his allowance. Not because you tell the kid, I got your allowance 'right here,' but because the kid needed the money, but he needed to earn it.
My point is, if you're going to give your guitars a new set of strings, it makes sense that they're expected to do the job they're supposed to before you can give them something new again. Rewarding good behavior instead of bribing bad behavior.
But since we're neither fathers/kids in this situation, here's a tip I learned from Bryan Ewald of PRS: Bryan said that if you switch to your neck pickup, turn your tone knob to 7 and your volume knob to 10, you'll effectively reduce too many overtones from interfering with proper tuning. You can intonate your guitar with these settings, but it's wise to use a quality stomp box or rackmount tuner that can provide a better read than a clip-on tuner. Since then, I can't say that I've been successful, but it helps do away with burning thru strings too often.
