I strongly recommend Solid Tech Racks of Silence for their sonic and aesthetic value. I’ve used them in my system for almost 20 years. They were originally recommended to me by Richard Hardesty, former high-end audio store owner and founder of the Audio Perfectionist journal. He also wrote a review on them which may be somewhere online. They’ve also been favorably reviewed by other respected reviewers (but Richard particular was an especially knowledgeable and no-bullshit reviewer/audio guy).
While I expect that the Solid tech is not at the sonic level of an HRS or Symposium rack, IMO it’s much nicer-looking, and crucially, a much-better value, i.e., you won’t be spending as much or more on an audio rack as a major component (though if you have a very high-end system, the other racks I mentioned may be a more marginal cost for the buyer). I’ve had a variety of heavy (e.g., 30-50 lbs), though not ultra-heavy gear in my ROS’s for years with absolutely no problems at all, and the ROS’s have improved their sound.
That being said, I tried their Discs of Silence footers (and was definitely NOT impressed by them), but their other tweaks, e.g., the Feet of Silence may offer better results.
FWIW, I also own a series of Symposium platforms and roller blocks and think well of them.