As someone who's never worked with David...
I think the key here is to understand what you're purchasing before you write a cheque. Understand that nobody can make you a star for $100 or $10,000. David's company and the many companies out there that are similar are consulting companies. They do offer a valuable service for a reasonable price, but it might not be the valuable service you think it is. Just like not even the best amplifier can make a great guitar player, even the best consulting advice isn't going to make you a lot of money if the rest of the pieces aren't in place as well.
I believe spending money on a consulting company is great if you need someone with a more business mind to help you make a plan for your project. 99% of the people making music don't have a plan, and I think it's crucial if you want to be successful. They can also introduce you to different areas of your job as a business person that maybe you hadn't thought of before, or give you leads into areas that maybe you have a shot at making some money. I mean, maybe your songs are never going to be at the top of the charts, but they might be ideal for a soundtrack in a movie or for a jingle.
If you know exactly what you want and how to get it, you probably don't need a consultant. You should spend 100% of your time getting what you want--- because afterall, you already know how to get it, right? But, regardless of whether you know how to get what you want or not, it doesn't make any progress to your own career to come on internet message boards and make an attempt to keep people from hiring him as a consultant, does it?
In a world as small as independent music, the ripoff artists don't have a hope in hell. The key to establishing a career in any industry (especially music) is to be upfront, honest, work hard, and offer a valuable service or product for the money you're charging. Looking at David's site, it seems that for $77, you get a load of information. $77 isn't that much money really, is it? I mean, if you're serious about what you're doing and really trying to make a living as a professional, $77 doesn't seem like a whole load of money to spend, even if you don't get that much out of it.
I frequently spend a couple hundred bucks on ad space that does absolutely nothing for me... so, getting a ton of information in exchange doesn't seem like that bad a deal.
"Get Rich Quick" isn't real anymore. David knows that and you should know that. In the music business, you're much better off to go with a "Do Okay After A Few Years Of Hard Work" method. It's a lot more realistic.
I hope my post here isn't perceived as an argument or challenge to your initial message. You may very well have been ripped off... in which case, I suggest you get a lawyer and prove your case to the court. If there are ripoff scammers out there, I'd love to see them get what they deserve... really. I've just never thought of David's company as one that made a career out of under-delivering or lying about what it is they provide.