I really love my Sierra ring sling! The colours are vibrant (as advertised) and makes a great fashion statement no matter what I'm wearing with it. The material feels sturdy and secure, and the rings provide a good grip that secures bub firmly in place.
I did take a couple weeks of practice before I felt that the cloth was broken in enough to make adjustments to the fit feel easy. I now use the sling pretty much every time we go out, and I sometimes prefer it over using the pram!