I watched those video's as well, and have had an older Milltronics for years. As for the stuttering, that comes from the g-code, I never used conversational and for what it's worth, it's supposed to be for quick and dirty stuff from people that don't program offline, so some stuttering there is pretty much of no consequence in my opinion. I've written lots of programs offline and had smooth, fast moves as long as the code didn't get into the .001 long 3D moves that something like Fusion is prone to generate, but remember, my control is from clear back in '92, processing time on the newer controls should be worlds better.
The spool down time looked overly long, again, might have to do with conversational. On mine I program spindle stop on the same line as the Z plus move, so it's stopping as it moves up and never had to wait for the spindle to come to a stop. Some of that could also be attributed to the parameters in the VFD. This is a "tool room" mill, not necessarily their heavier duty "production" machine the 3018, which has a whole lot more spindle hp and might get with the program better.