I have a Darbee Darblet added into my system and really REALLY like it. It was a little strange at first as you do have options to tweak it and there is a fine line between getting maximum improvement and it being too artificial looking. I have mine on all the time and never adjust it at this point. Sure, there are some movies where they have a lot of film grain (added by the studios to make things more "gritty") like The Grey with Liam Nieson and a bunch of wolves. That was really grainy already and the Darbee system will "enhance" the grain too. For films with less grain added to them than in The Grey, they are just fine.
I just wanted to mention that no system is perfect, but this technology is pretty darn cool. Cool enough to buy an Oppo with it if you already have an Oppo without? Not sure. You could just buy the add-on box that works with anything. I have it set between my receiver and my projector. Then EVERY source gets enhanced and not just the blu-ray player. Then again, it currently costs around $300 or a little more. I got mine for just $165 back as a pre-order special.
EDIT: WOW. I just saw that the Darblet is running $320 at Amazon and the Oppo 103D is selling for $600. Crazy that the Darbee technology is that much vs. the Oppo with the tech inside it.
M60s, VP180, VP150, QS8s, SVS 20-39PCi, HTPC, JVC RS45, Onkyo TX-NR709, Shakers