I like Etsy a lot, and a lot of the sellers provide really high quality work. But it's also true that I generally only buy from people with a large number of positive reviews and a small to none number of negative ones. It's kind of like with any online market - you just have to do your research.
I'm not too familiar with Etsy, I know what it is but I've never ordered from there. Just be sure to check up on who you are buying the product from. I imagine there are ratings and possibly reviews about sellers, so check those out to be sure you know what you're buying from whom.
Are the products good? What an odd question to ask about a site filled with tens of thousands of crafters, each selling their own individual items. If you like what a piece of jewelry looks like and you feel the price is worth the item, then buy it. That pretty much goes for all things. I've never had to return anything I've bought from an Etsy seller.