i was recently looking at clip-ons as mine fell off and I stood on it. Anyway, back to the point, I like to go 'stealth' with my clip-on and clip it on the headstock so I can see it 'from the back' if that makes sense. I rejected a Polytune Clip as it would only seem to go on the front of the headstock and is to my mind, ugly. So if you go 'round the back' it is important to have 3 D articulation so the display faces the right way. My most recent cheapy doesn't and I have to read it at 45%.
FTR I also have a Korg pitch black...in blue!