I remember the parrotsecrets site (that sold an e-book on how to care for parrots, and apparently made tons of money doing so) and it looked a lot like this site. Maybe that kind of design actually does sell better. But as you say - A/B tests will prove or disprove it.
I got only positive feedback from buyers and my total conversion is really not bad. First I want to make a few bucks and then invest to design. Just my rule - first make money then spend it...
If you are selling to a semi-technical audience, it will just turn them off. "Intelligent" people are horribly afraid of falling for a scam, because not only does it mean they get ripped off, but it attacks their self-image directly.
So if you look like a scam, they're going to assume you are.
