I’ve got several of Reefing Arts racks and they ARE quality. My tank has 3/4” glass, so finding anything with a strong enough magnet is a challenge.
The medium is my favorite because it’s the most stable on my tank. The large is a great size but with just the same two magnets the medium has, it struggles on my thick glass. I think a third magnet would make this perfect.
I also have the small one that just has one magnet. That one “works” but I have to be super careful not to bump it or else it will flip over and I definitely can’t move it from the outside like I can the others with two magnets. Not sure this would happen on tanks with thinner glass, but suspect it would. A second magnet would make this rock solid.
BTW, their customer service is great too. Very responsive.