I've had those ring for about a week. First thoughts were that unlike other reviews I found the sizing true to size, in hindsight I would have got the 9 over the 8. I also felt like the gold does look nice. Wearing it next to my other jewellery it does look real and fine.
HOWEVER I had such low expectations for a $30 fitness ring and I've been very impressed. I've worn it a few days alongside my Garmin and the step tracker is close enough to being the same that I wa every pleasantly surprised. I've used the sleep and heart rate feature and they work, although I don't have anything to compare the results too.
Battery life has also been excellent, app is really easy to use.
Overall for the price point would definitely recommend for anyone interested in a more subtle fitness tracker than a watch and for an excellent price point.