I decided to get this after reading all the reviews here, and I'm glad I did. The earplugs fit surprisingly well on my ears (I'm an adult Asian female - was scared that it will be too big) and it's quite comfortable to wear too. Though I only wear it for about 30 mins, so still need to be tested for longer period.
The noise reduction is as advertised - I was using it for a band practice and didn't have any ringing afterwards. It reduces more of the higher frequencies so high-pitched sounds will be muted more. Note that it only reduces the overall volume to a more acceptable amount, it might still be too loud for some people. But for musicians who still need to hear various sound while protecting the ears, this does the job well :)