I have preferred the Avant mounts for years. The weight is the price you pay for a bombproof shock. Scratches mics? I could see if the mic is rubbing against the metal construction, but the o-rings seem to work just fine for me. The picture is deceiving and I can't believe they show them with three rings on each side. I only run with two and the mics go in with no resistance. The site now mentions that they ship with only two rings per side now. They also come with a 5 year warranty.
Personally, I was tired of plastic mounts with cheap plastic (or metal) joints that would fall apart simply from normal use. I have a pair of Superluxes, which I find to be fine shocks and have held up over the years, but they are cracked in the joints and I don't trust them with any weight. One gets used for an 'active' kwon-type setup, though.