I really don't think it's simply a choice between honest or dishonest. Sales is telling a story. It's your opportunity to craft a narrative complete with good guys, bad guys, a quest to solve a specific problem, and a happy ending of how successful your prospect will be if they buy your product. You can highlight the weaknesses of your own product and actually improve your case by then explaining why these aren't actually weaknesses at all. These aren't the droids you're looking for... Further, a product is more than the sum of its features, just like your career is more than the sum of your resume and your life is more than the sum of your bank account or how many trophies you have on your wall. Sell the big picture.
Also, if your product really does suck, get a job working for someone who has a better product. If no one has a better product, build it or do the best you can with what you've got. There's quite a bit of that in software where the best product simply doesn't exist yet, so sell the current best despite its shortcomings. Great salespeople have to be sold on the product they're selling before they're willing to sell it to someone else--it's easier for everyone that way.
Sales is all about understanding people quickly and helping them get to where they want to go, I'm not sure why technical people often have a problem with this but I suspect it has to do with an underlying lack of confidence when it comes to people and asking for things; it's not that they're inherently more honest than people who work in sales, I've heard that one plenty and I find "honesty" (as they see it) is usually just an excuse for their timidity, something to hide behind. And your average salesperson probably is a hack, but so is your average engineer.
Also, if your product really does suck, get a job working for someone who has a better product. If no one has a better product, build it or do the best you can with what you've got. There's quite a bit of that in software where the best product simply doesn't exist yet, so sell the current best despite its shortcomings. Great salespeople have to be sold on the product they're selling before they're willing to sell it to someone else--it's easier for everyone that way.
Sales is all about understanding people quickly and helping them get to where they want to go, I'm not sure why technical people often have a problem with this but I suspect it has to do with an underlying lack of confidence when it comes to people and asking for things; it's not that they're inherently more honest than people who work in sales, I've heard that one plenty and I find "honesty" (as they see it) is usually just an excuse for their timidity, something to hide behind. And your average salesperson probably is a hack, but so is your average engineer.