i'd go polytune mini.
I've heard that the Pitchblack Poly has some issues with switching between poly and standard tuning modes independently. I'll still stick with my current Pitchblack if it's all the same.
The only thing that makes me consider getting the Pitchblack Poly is that they seemed to have improved the LED display to function better under bright outdoor conditions.
If I'm not wrong the Polytune intelligently changes the LED intensity according to the lighting, thus making your daytime outdoor tuning a possible scenario.