I find that our tuner's precision is very very high.
The Axe-Fx, with its spinning 8-BALL has the greatest precision of any tuner we offer. Using a test oscillator plugin in Logic, I was able to see differences in the speed of the spin between in changes as ridiculously small as 440.00 Hz and 439.99 Hz. The center "dot" offered on the Axe-Fx and AX8 is also extremely precise, registering a shift of one pixel when the pitch changed from 440 Hz 439.96 Hz. The ARROW indicators have a slightly more coarse precision. In my test, the left arrow switched off at 439.28 Hz -- so even this more granular indicator is still very precise.
So in short, I think the AX8 has an extremely precise tuner -- probably more precise in my opinion than you would need for guitar intonation, given that even the best instrument in the world will be out of tune by a greater degrees with the variation from one pick strike to the next, or as you change your posture, move, etc.