No one buys anything from DesignByMe, its stupidly expensive.
That said, I love LDD. I don't know who their target audience is, but my 8 year old sister LOVES it, its certainly not too hard for her. I'll be really PO'd if they get rid of LDD.
I did when it first started, I have ordered at least 6 of my creations and at the time I believe the cost was only a mere 40 % more then if you were to buy from pick-a-brick.
Best way to tell is simply average cost per piece.
Today though, that cost is more than doubled, for example. My latest LDD creation is 2213 very basic pieces at a cost before taxes at $450.31 Canadian,
where the Lego exclusive "Fire Brigade", a modular kit is 2231 cool pieces and only 199.00 to buy
http://shop.lego.com/en-CA/Fire-Brigade-10197Seems that in itself should tell you something...