Does anyone know if some colors or quality PLA is more prone to warping than others. In other words: do cheaper PLA filaments warp more than expensive filaments?
You’re going to find differences between different kinds of PLA. The main thing contributing to warping is going to be variance in the melting point. Different dies and manufacturing processes can adjust the composition enough to change the melting point, maybe as much as +/- 10C. If your hot-end is out of line with the melting temp of that particular PLA, you’re certainly going to see warping or other problems like that.
Lots of air/water in the PLA will also lead to problems with inferior stuff, which can cause inconsistent flow or sputtering.
You should calibrate your printer for each roll of filament if you have the patience.
This is all true of ABS too, and should hold for really any spool of filament.