I recently purchased an engagement ring for my girlfriend from Brilliant Earth, and I don't regret the decision at all. I ended up starting there actually because the promise of conflict free diamonds and recycled gold, silver, and platinum bands seemed kindof neat, and my girlfriend and I are into the whole environmentalism thing.
I decided to try the "make your own engagement ring" option, which I'd always liked the idea of, because I've just never been satisfied with a lot of the ones that I've seen. It was very easy to choose the setting, the stone and the band, and the price was within what I was expecting to spend on an engagement ring. So under careful scrutiny I picked out all the details and designed the ring, I thought it looked great, but I just wasn't positive yet.
I left the page up on my computer for about a week, and every time I came in from a bad day at work, I'd see the ring and smile. Once I realized that just looking at the ring made everything feel right, I decided I had to get it.
After placing the order I received a personal confirmation email from their gemologist, who told me that "the ring is beautiful!" and was very polite. When I had issues accepting the delivery a Brilliant Earth employee sent me an email offering help before I'd even thought it might have been a problem.
Moral of the story: Ethical and environmentally friendly company with fine products and fantastic customer service.