I can say that so far DMD has proved its theory with me... for example... nearly 2 years ago I didn't have much cash, but I used my whole tax return on an investment in DMD.
I spent 5-7k US total (can't remember exactly) and purchased a 'Legendary 10' address, a promotional address DMD was offering, as well as about 12k DMD coins.
For a while there, I wasn't sure that my investment would be amazing, and nearly sold it... but I'm SO GLAD I didn't...
When DMD released v3.0, they decided to honor their Legendary 10 holders, by providing them with a MasterNode! This MasterNode doesn't allow the holder to spend the initial 10k coins, but they CAN spend the coins that the MasterNode mints. :) This was a VERY fair trade, IMO.
So I was given a MasterNode, which has already made me over 200 DMD coins! I also had a nice chunk of DMD left (after selling a few earlier due to necessity and other purposes.)
I sold a chunk of my remaining coins, to provide the USD necessary to PUT A DOWN PAYMENT ON MY HOME!
So... not only do I now have a node that brings me around 80-100 USD per DAY, but I also have a down payment on my home... ALL of this... from a 5-7k USD investment nearly 2 years ago...
If this isn't a success... I don't know what is!
Thanks for your support for DMD 2 years ago. May your Masternode provide for you for a long long time into the future. You deserved it, and you deserve it. Keep it up mate.