What does happen?
When writing complex shapes fast (e.g. writing cursive fast), the digital ink appears as if there is some smoothing going on, but I believe it is down to insufficient sampling rate of the pen / digitizer.
What should happen?
As far as I know, Surface samples at 140 Hz, and iPad Pro does so at 240 Hz.
From my experience, I do feel the difference when writing on my iPad Pro vs. others, so I believe 240 Hz would significantly improve the pen experience.
With the DV8P, there was even an enthusiast who wrote their own program to manipulate the sampling rates on it and it made a huge difference - thus proving (though Dell wouldn’t acknowledge) that it was something that could be addressed with software if they’d just step up and deal with it.