Pulse: Stable enough. The left-right position adjusts very easily by loosening the fixing device (not the screw that holds the footplate..)
The support plate seems sufficient for the Presonus Studio 8 monitors.
Minus (for my needs): They are too high at minimum as studio monitors at the desk. The tweeters are too high without adding any foam dampers. Solutions: raise the chair or tilt the speaker with different foams.
In terms of height, I found these to be the most suitable. The build quality is okay, I'm satisfied. However, the mounting system for the monitor support could be improved. A sliding system on the horizontal axis is recommended to safely adjust the orientation (direction) of the monitor. If you choose to change the working angle with the monitors, that mounting system loosens, and you have to take the monitor down and tighten it with an Allen key. Basically, changing the angle (left/right) loosens the previously tightened screw.