I was wary of buying something as expensive as an engagement ring from a store I hadn't dealt with or heard of before, but the prices were excellent, and my credit card company is good at disputes, so I took the chance. And I'm glad I did. This is a great company.  
 
I'd checked Blue Nile and some wholesalers (local and online) along with the standard jewelry stores (Kay, Reeds, etc). I'd been to pricescope.com (a must for anyone shopping for a diamond) and done my research. I'd found what I thought were some decent prices, but DiamondOnNet blew them all away.  
 
I then accidentally wandered onto their development site and ordered the ring based on outdated platinum prices, saving me $400. And they actually honored the price mistake - not something you see very often anymore. (For those of you who are thinking about doing it on purpose, the problem has been fixed, and orders can not be placed on the development site anymore). Even without the price mistake, their prices were much better than anyone else.  
 
I then called and spoke with Bijan, who picked out an absolutely stunning stone for me. I was afraid that it may not be exactly what I was looking for, but I realized when I got it that I should just trust the expert. I've seen lots of stones, but never one this nice, and definitely not for that kind of price.  
 
They have an option (which I took advantage of) where they will send you the setting and stones, loose, before you actually purchase them, for pretty much just the cost of shipping ($20). It really helped me feel better about the whole process, because I wasn't sure who these people were or if they were even legit. There was a slight miscommunication, so for those of you who want to use this option - the diamonds come finished, polished, and ready for use, but the setting is still a little rough and unfinished. It looks good, but not as good as it will eventually. We got it all sorted out, though, so I'm still happy overall.  
 
I ended up getting a 3-stone platinum ring with a tcw of 1.36, including a center stone that's ideal cut with hearts & arrows and D-colored, for under $3000. I couldn't be happier.  
 
I'm not saying you should definitely order from them. If they hadn't had a setting I liked, I doubt I would have. But don't count them out. They have customer service like they used to, and like all companies should - quick, attentive response, and the customer comes first.