How fast are you able to print?

[Humanzee]

I've slowly pushed my way up to printing PLA at a max speed of 120mm/s, with things like the first and top layers at various slower speeds depending on the print, all at 235C, and I see no reason not to push for faster. The only time I've seemed to be pushing against limits is when I have to dial the non-print movement speed down from 300mm/s when there's a print that approaches the print area boundaries, or else a belt is liable to skip and start making crazy and undesirable things happen.

I'm sure people are going even faster. How fast? How do you do it?

Alternatively, why do you prefer to print slower?

[Polygonhell]

I've printed at >100 mm/s, but I almost always run at 30mm/s these days, with somewhat faster infill.
As to why, it's in the sweet spot for print time, and quality.

As to why it's in the print time "sweet spot", 60mm/s isn't 2x as fast as 30 because acceleration, Jerk and minimum layer times become dominant. i.e. large increases in print speeds result in smaller decreases in print times. I usually trust the KissSlicer print time estimate and just move the slider until I hit what I perceive to be the knee in the curve and that's usually ~30 mm/s.
I'm also usually not in a rush for the part. If I have a particularly large print, I might go faster, but it's usually easier to decrease print times with greater layer height.

I also usually print PLA closer to 180 or less. Unlike ABS, PLA gets more and more liquid as temperatures increase and that affects the final color (yes really) and IME affects surface finish.