I used these pads as an addition to monitor stands. They served me good for six years. These pads are very affordable, if you are on a budget, I recommend them highly. They started deforming after a while (monitors leaning on the right side, could be my Yamaha HS-5's are a bit heavy for them)
Pro: Durable, adjustable, affordable.
Con: Some deformation occurs after years of usage, strong smell when they are new (helps to leave them on outside air for a while)