This is an amazing offering - I love that a store is focusing on pet jewelry (even though you can put anything inside). 
First, I LOVE my ring - it is 100% exactly what I wanted, especially at this price. 
But a note: this is not everyday jewelry. These are special occasion pieces. They will not hold up to everyday wear and tear. BUT wearing them on memorable occasions will make them more important. 
For the review:
I got the heart shaped gold color ring in 6. I'd say it's pretty true to size. Easy to open (I hope the clasp doesn't wear easily). I wish they had more shape options and ones without the "gems" - I think I saw a new mother of pearl one which is great - but plain or a nice etching would be wonderful, and in square or diamond. 
Now, go buy one (while I buy a couple more for everyone I know). I wanted to add photos, but I guess that isn't supported. Just know they look beautiful and I've gotten many compliments.