I have both, the clip on I use is one that tucks under the headstock pretty well and is barely visible. I still prefer the pedal but for the reasons other than accuracy. Once I calibrated the clip on to a pedal tuner, when I've occasionally compared them they give essentially the same results. There are mini tuners like the Polytune that might fit on a board that a TU-3 wouldn't. Also, if you go to the trouble of putting on and taking off your clip on every time you tune, just carrying a pedal tuner seperate from your board and adding it to the front when you set up has to be over all way less of a PITA. Putting on and taking off the clip on isn't that tough of course, but repeating it several times would get to be a bit of a pain and might discourage using it as much as you need to.