I have a par of those, one for lighter, one for heavier mics. Both perform brilliantly for several years now. Highly recommended to any home studio owner.
PROS: great vibration isolation, grabs very securely any mic, even heavy ones, or ones with unusual body shape like the square'ish Sennheiser MD-421.
CONS: can sag a little if you leave a heavy mic in it overnight, best to remove the mic if not in use.