I personally think buying a Diamonna is worth it. I recently got engaged and was wearing my Diamonna when I saw my family for Thanksgiving. One of the women in my family is also engaged so I got another chance at comparing a diamond to my stone. There is nothing poor quality about the Diamonna stone. The cut and optics of my stone are spot on. My family wouldn't believe that it wasn't a diamond in my E-ring
I can't really speak about a Quorri stone as I've never seen one. I also haven't had my Diamonna for very long either so I cannot speak for the longevity of the stone (I am not worried as my jeweler knows how to clean SiC gems). If you are interested in Diamonna, you ought to give Ron Hansen a call or better yet, go visit his showroom in Ashland, Oregon. Anyway, thats my $0.02, hope it helps!