I'm shitty at self-promotion, no doubt a result of some deeply-rooted inferiority complex. Yet the most successful people I've worked with have been constant self-promoters, and it doesn't seem to trouble anyone provided it's done with transparency and enthusiasm, and that the promise is more or less delivered.

To me the worst of both worlds is the promotion that shuffles its feet and and says "Gosh I'm not good enough but maybe you could have a look anyway?" That just takes up people's mental energy while subliminally sending the message that it's a waste of time because they really aren't good enough.

As noted above, if the product really does suck, then it's a fool me once type situation. But yours doesn't.