[BrianG]

Ever feel the difference between a Neu and a Feigao just by spinning the shaft with your fingers? On the Neu, you can REALLY feel the magnetic detents. I just assumed slotted would be better since the magnetic field seems to be far more concentrated. OTOH: A slotless design has a wider magnetic field (since it isn't concentrated by a core) so it makes sense that the power delivery would be smoother. It also makes sense that some ESCs would have issues with a slotted motor since the back EMF pulses are much more intense.

Also, coreless coils don't saturate magnetically as easily and are more linear, which is why coreless inductors are used in high-end audio crossovers.