Being honest and transparent does not necessarily mean putting everything out there on the table at once. When I meet someone - say, at a networking function - if I know a lot of people in that field, I'll ask the person what's different about what they do. The guy who owns an embroidery company said he uses some techniques others don't know about. He told me about one in particular, and then added, "But it doesn't work well on light colors, like pastels. You have to use a darker color." When I suggested he might not want to lead with that statement, he countered that he was always honest.
Well, I wasn't suggesting he lie. I wasn't saying he should go ahead and make whatever the customer ordered and then, once they had the completed order in their hands and were displeased with it, say, "Oh, yeah, I knew that wouldn't look good. You can always place order another in a darker color." I was just suggesting that he not mention that until he got the prospect interested in doing business with him. If they liked that particular process, then he could tell them to use dark colors.
When you dated, did you ever start out thinking, "Oh, I could never date someone who (fill in the blank), and the find out the person you were seeing did or was just such a person? If you had known that about them up front, you may never have dated them. But now that you'd gotten to know them, well, maybe that's not so bad.
Just as there are some things that are not first-date conversation, there are some things about your product or service that are not the strongest selling point. Don't open with those! Open with what will get the prospect turned on, get them excited about buying from/working with you. Tell them all the advantages, what makes your product/service better than others, how much help their business, whatever. And when they express an interest and want to talk terms, say, "That technique is great, customers love it. But your logo will not show up well on this. It'll look great this way."
I had thought this would go without saying, I had thought that guy was an exception. But it turns out, it's not and he wasn't.